Fix CreateFileW function usage, otherwise it fails to open file.
Merge pull request #501 from vadimi/master

Fix CreateFileW function usage, otherwise it fails to open file.
Fixes build to report correctly to coveralls.io
Straightens out some issues introduced with PR#476

The construct in sass_interface.cpp is evil:
source_comments(!c_ctx->options.source_comments)

Fix for omit_source_map_url (never propagated to cpp_ctx)

Removed superfluous source_maps option on struct