Fix some whitespace inconsistencies
Fix up comments
Add PLClangCursorKindPackedAttribute
Remove trailing whitespace verification in testBlockCommand

Clang changed its behavior to discard this trailing whitespace for block
commands.
Add PLClangTypeKindMemberPointer
Convert unit tests to XCTest
Reorder PLClangObjCPropertyAttributes to use first bit
Fix system header tests on 10.9

10.9 no longer includes system headers, to work around this set an
SDKROOT preprocessor define to the same value as the equivalent build
setting. This is value is then passed as the -isysroot argument when
parsing translation units in unit tests.
Fix linking with clang-3.4
Merge branch 'master' into doctool-prototype