Release 1.2.0

Enhancements:

• Improve failure reporting for in; allow it to be combined with more etc. #11
• Add support for mocking return values in side-effects.
• Add support for optional message argument in expect. #9

Documentation:

• Added article-style documentation for cljdoc.org. #6, #7, #8, #10
• Add example of more-> equivalent to thrown-with-msg?. #5