add semaphore.check
Merge pull request #8 from ostinelli/semaphore

Add semaphore.check
improve fs changes tracking
replaced VDKQueue with dispatch-ing
release 9b426bc
formatting
updated screenshot
do not blow up if task cannot be launched
copy observers to avoid in-loop array modification
release 12227a3
box dispatch_source_t when saving them off into a dictionary
use BRIDGE_CAST macro
release 0f2f271
fix zombie dispatch sources
release b7f4023
make Xcode happy about hidpi artwork in CheckmanTests
first pass at travis.check
separate included ci checks into a Xcdoe group
minor tweaks to semaphore.check
simplify Rakefile; check included check ruby syntax as part of rake