docs: Update documentation [ci skip]

Remove references to docopt and update help screen.

Author: acgetchell

README.md

@@ -46,7 +46,6 @@ including the foundations and recent results, please see the [wiki](https://gith
 [Causal Dynamical Triangulations][CDT] in [C++] uses the
 [Computational Geometry Algorithms Library][CGAL], [Boost], [TBB], and [Eigen].
 Arbitrary-precision numbers and functions are by [MPFR] and [GMP].
-[docopt] provides a beautiful command-line interface.
 [Melissa E. O'Neill's Permuted Congruential Generators][PCG] library provides high-quality RNGs that pass L'Ecuyer's
 [TestU01] statistical tests.
 [doctest] provides [BDD]/[TDD].
@@ -71,7 +70,6 @@ Arbitrary-precision numbers and functions are by [MPFR] and [GMP].
 - [x] 3D Simplex
 - [x] 3D Spherical triangulation
 - [x] 2+1 foliation
-- [x] Integrate [docopt] CLI
 - [x] S3 Bulk action
 - [x] 3D Ergodic moves
 - [x] High-quality Random Number Generation with M.E. O'Neill's [PCG] library
@@ -211,13 +209,12 @@ along with several others.
 
 ## Usage
 
-CDT-plusplus uses [docopt] to parse options from the help message, and so
+CDT-plusplus uses [program_options] to parse options from the help message, and so
 understands long or short argument formats, provided the short argument given
 is an unambiguous match to a longer one. The help message should be instructive:
 
 ~~~text
 ./build/src/cdt --help
-cdt started at 2023-01-03.14:44:22PST
 Causal Dynamical Triangulations in C++ using CGAL.
 
 Copyright (c) 2013 Adam Getchell
@@ -228,28 +225,38 @@ to the Metropolis algorithm. Specify the number of passes to control
 how much evolution is desired. Each pass attempts a number of ergodic
 moves equal to the number of simplices in the simulation.
 
-Usage:./cdt (--spherical | --toroidal) -n SIMPLICES -t TIMESLICES [-d DIM]
-            [--init INITIAL] [--foliate FOLIATION] -k K --alpha ALPHA
-            --lambda LAMBDA [-p PASSES] [-c CHECKPOINT]
+Usage:./cdt (--spherical | --toroidal) -n SIMPLICES -t TIMESLICES
+            [-d DIM]
+            [--init INITIAL RADIUS]
+            [--foliate FOLIATION SPACING]
+            -k K
+            --alpha ALPHA
+            --lambda LAMBDA
+            [-p PASSES]
+            [-c CHECKPOINT]
+
+Optional arguments are in square brackets.
 
 Examples:
 ./cdt --spherical -n 32000 -t 11 --alpha 0.6 -k 1.1 --lambda 0.1 --passes 1000
-./cdt --s -n32000 -t11 -a.6 -k1.1 -l.1 -p1000
+./cdt -s -n32000 -t11 -a.6 -k1.1 -l.1 -p1000
 
 Options:
-  -h --help                   Show this message
-  --version                   Show program version
-  -n SIMPLICES                Approximate number of simplices
-  -t TIMESLICES               Number of timeslices
-  -d DIM                      Dimensionality [default: 3]
-  -i --init INITIAL           Initial radius [default: 1]
-  --foliate FOLIATION         Foliation spacing between timeslices [default: 1]
-  -a --alpha ALPHA            Negative squared geodesic length of 1-d
-                              timelike edges
-  -k K                        K = 1/(8*pi*G_newton)
-  -l --lambda LAMBDA          K * Cosmological constant
-  -p --passes PASSES          Number of passes [default: 100]
-  -c --checkpoint CHECKPOINT  Checkpoint every n passes [default: 10]
+  -h [ --help ]                 Show this message
+  -v [ --version ]              Show program version
+  -s [ --spherical ]            Spherical topology
+  -e [ --toroidal ]             Toroidal topology
+  -n [ --simplices ] arg        Approximate number of simplices
+  -t [ --timeslices ] arg       Number of timeslices
+  -d [ --dimensions ] arg (=3)  Dimensionality
+  -i [ --init ] arg (=1)        Initial radius
+  -f [ --foliate ] arg (=1)     Foliation spacing
+  -a [ --alpha ] arg            Negative squared geodesic length of 1-d
+                                timelike edges
+  -k [ --k ] arg                K = 1/(8*pi*G_newton)
+  -l [ --lambda ] arg           K * Cosmological constant
+  -p [ --passes ] arg (=100)    Number of passes
+  -c [ --checkpoint ] arg (=10) Checkpoint every n passes
 ~~~
 
 The dimensionality of the spacetime is such that each slice of spacetime is
@@ -262,8 +269,7 @@ links (in 2+1 spacetime), and the timelike faces (in 3+1 spacetime).
 
 ## Documentation
 
-Online documentation is at <https://adamgetchell.org/CDT-plusplus/> automatically
-generated by [Travis-CI].
+Online documentation is at <https://adamgetchell.org/CDT-plusplus/>.
 
 If you have [Doxygen] installed you can generate the same information
 locally using the configuration file in `docs\Doxyfile` by simply typing at the top
@@ -407,10 +413,8 @@ Optional:
 
 - [vcpkg]'s version of [date] has an unfixed bug [#23637] which produces `use-of-uninitialized-value` in [MemorySanitizer].
 
-- [docopt] also has a `use-of-uninitialized-value` bug ([#149]).
 
 [#23637]: https://github.com/microsoft/vcpkg/issues/23637
-[#149]: https://github.com/docopt/docopt.cpp/issues/149
 [CDT]: https://arxiv.org/abs/hep-th/0105267
 [CGAL]: https://www.cgal.org
 [CMake]: https://www.cmake.org
@@ -425,7 +429,7 @@ Optional:
 [Doxygen]: http://www.doxygen.org
 [Homebrew]: https://brew.sh
 [Ninja]: https://ninja-build.org
-[docopt]: https://github.com/docopt/docopt.cpp
+[program_options]: https://www.boost.org/doc/libs/1_85_0/doc/html/program_options/tutorial.html
 [Mathjax]: https://www.mathjax.org
 [GraphViz]: https://www.graphviz.org
 [Eigen]: http://eigen.tuxfamily.org/index.php?title=Main_Page