Misc. bug fixes and performance improvements
- Skip v1.12 because tag already exists and Travis CI/CD won't re-trigger a tag that has triggered it
- Made exclusion marker scanning much more efficient:
- fastcov will do a preliminary scan to see if even a single marker is in the file before processing it; otherwise it early exits
- fastcov now spawns multiple processes to scan for exclusion markers instead of multiple threads
- This should result in significant speed gains if a) you have a lot of cores, b) you have a lot of source files
- Otherwise you probably won't notice
- Fixed issue where fastcov sometimes crashes if gcov is fed an empty gcno/gcda file
- Fastcov no longer crashes and will instead skip those source files, print an error, and exit with status code 8