Mention some of the essential features in the README

Author: bbatsov

README.md

@@ -12,6 +12,21 @@ auto-completion and a minor mode (`inf-clojure-minor-mode`), which
 extends `clojure-mode` with commands to evaluate forms directly in the
 REPL.
 
+`inf-clojure` provides a set of essential features for interactive
+Clojure(Script) development:
+
+* REPL
+* Interactive code evaluation
+* Code completion
+* Definition lookup
+* Documentation lookup
+* ElDoc
+* Apropos
+* Macroexpansion
+* Support connecting to socket REPLs
+* Support for Lumo
+* Support for Planck
+
 For a more powerful/full-featured solution see [CIDER][].
 
 ## Installation