-Fixed header install subdir being turned into an absolute path instead of a subdir, and thus blowing away the prefix
-Fixed --incdir and --libdir to be able to take project macros
-Fixed --install with multiple targets trying to re-install the same headers multiple times
-Fixed c headers ignoring header subdir
-Completely removed os..cwd() from ResolveFilesAndDirectories() as it's unsafe due to threading. Using project.workingDirectory instead.
-Fixed exclude directories, include directories, and various other directory lists (any list of directories that's run through ResolveFilesAndDirectories()) essentially memory stomping when building with multiple targets