Less implementation specific docs for -mapcat

Fixes #24
Don't use the word collection when meaning list
Add -when-let and -if-let macros
Merge pull request #26 from shosti/when-if-let

Add -when-let and -if-let macros
Add Emanuel Evans to list of contributors
Add -insert-at (closes #27)
Merge pull request #28 from shosti/master

Add -insert-at
Update @shosti's list of contributions.
Typo
Fix -when-let and -if-let docstrings
Add -when-let* and -if-let*
Merge pull request #29 from shosti/when-let-multi

-when-let* and -if-let*
Release 1.2.0
Avoid unnecessary copying for -insert-at
Merge pull request #30 from shosti/insert-at-opt

Small optimization for -insert-at
Add -partition-in-steps & -partition-all-in-steps
Release 1.3.0
Add new functions to syntax highlighting
Release 1.3.1
Fix bug with -partition-all-in-steps