git Directory Reference

Files
	test_git_compare_handler.cpp
	Regression tests for the shared KIGIT git helpers ResolveRefToTree / CollectDiffDeltas and the CompareRefs façade built on top of them.
	test_libgit_backend.cpp
	Regression tests for LIBGIT_BACKEND, KIGIT_COMMON, GIT_INIT_HANDLER, GIT_PULL_HANDLER, GIT_PUSH_HANDLER, GIT_COMMIT_HANDLER focused on the recent Git integration bug fixes and the Amend Last Commit feature.