Add if-let and when-let
Merge pull request #8 from qerub/if-let+when-let

Add if-let and when-let
Add `version` to info.rkt and set it to 0.1

Since this is changing more than I expected, it would be helpful to
have a version for other packages to depend on. For example if they
need `if-let` or `when-let` they can say they need 0.1.
Change some indented code blocks to racket fenced code blocks.
Change more indented code blocks to racket fenced code blocks.
Fix typo
Change formatting on blockquotes: Bold "NOTE:" or whatever.