Corrected CTRunGetPositionsPtr usage

CTRunGetPositionsPtr can return a NULL result. This correction handles
that result, copying positions using CTRunGetPositions.
Merge branch 'keremerkan-master' into develop
removed superfluous warning
Updated to DTFoundation 1.7.1
Updated podspec for 1.6.13
Implemented animated GIF support
Merge branch 'od/issue_705' into develop
Migrated Mac and iOS unit tests to XCTest
Merge branch 'od/xctest' into develop
Trying to fix unit test
Removed invalid references from Demo scheme
Removed BundleLoaderDummy from unit test to see if this lets the build go through
Retagged 1.7.1 of DTFoundation
Removed BundleLoaderDummy, does not seem to be necessary any more
Added unit test for #780
Preserve margin values parsing "margin-*" style values after "-webkit-margin-*" values, fixes #780
moved DTCoreText.h import to PCH
testing #780
Merge branch 'od/issue_780' into develop
Added unit tests for #738