Added commented xcconfigs for App bundle vs. sub_umbrella Framework Target build.

Also fixed method mismatch in updated NSTimer call in demo app. and
erroneous 10.9 deployment targets.
Fix macro parentheses.
Fix BK_EACH and BK_APPLY macros.
Fix BK_REDUCE macro.
Merge pull request #172 from mralexgray/feature/sub_umbrella

Added commented xcconfigs for App bundle vs. sub_umbrella Framework Target build
Add tests for macros.
Change variable prefix from MA_ to BK_.
Add BK_NEXT macro.
Remove wrapper from BK_APPLY because the order is undefined.
Merge pull request #173 from nschum/macro-fixes

Fixes and supplements for collection macros