Merge pull request #14 from garnett/master

Get rid of absolute paths, remove xctool
Fixes https://github.com/adamwaite/iOS-Build-Kit/issues/15. Added option to clean before build.
Fixed: https://github.com/adamwaite/iOS-Build-Kit/issues/16. Build succeeded now goes from exit code rather than strings.
fixed README glitch
validate tests passing on exit code rather than output.
Merge branch 'master' of github.com:garnett/iOS-Build-Kit into garnett-master

Conflicts:
	lib/ios_build_kit/tasks/xcode_build.rb
Removed merge tmp files