Fastcov

Description:
- Fix 48, 53
- Fix reported info metrics
- Filter options, exclusion marker scanning can now apply during combine operations
- Allow LCOV_EXCL markers to filter function coverage
- Shift exit codes to start at 3 (slight break in backwards compatibility if switching on exit code values)
- This is because 1-2 have special meaning for a lot of shells
- Add new exit code (6) for exclusion scan failure

Description:
- Fix 43 (reduce memory footprint of fastcov)
- Refactor GCDA processing to use `multiprocessing.Process` instead of `threading` (should result in 15%+ speedup on larger projects since each gcda worker can now bypass GIL and leverage additional cpu resources)
- When branch lists mismatch, overlay smaller list on bigger list
- Add option `--skip-exclusion-markers` to skip the step where fastcov scans source files for exclusion markers
- Add SPDX license id and url

Description:
- Fix 32, 37, 39, 41
- Remove mutual exclusion for file filtering flags
- Fix potential IndexError that could occur if both including and excluding branches
- Remove support for gcov-json output (nobody uses it)
- Enhance fastcov json format to support lcov test names. This causes a slight break in backwards-compatibility but I doubt anyone will notice since most people use lcov info format.
- Add `--test-name` CLI option (equivalent to lcov's `-t`) to support test names (i.e. for use with `genhtml --show-details`)
- Add `--add-tracefile` CLI option (equivalent to lcov's `-a`) to support coverage combine operations (i.e. for use with `genhtml --show-details`)
- Add `--verbose` CLI option which prints more debug details (i.e. which coverage files are being skipped/filtered, and why)

Description:
- Fix 17
- Fix 33
- This release could cause some slightly different filtering behavior depending on CMake build system type you are using.
- This release standardizes filtering to always use absolute paths so that the filtering behavior when using Make vs. Ninja builds are the same.

Description:
- Fix 28
- Add ability to process gcno files in addition to gcda files by passing `--process-gcno`
- This flag essentially includes *all* instrumented sources files in the coverage report, not just ones under test.

Description:
- Fix 14 and 15
- Add ability to specify file encodings with `--fallback-encodings`; You won't need this option unless one of your source files is saved with a non-utf8 encoding
- Add automated testing and deployment
- `test/` now contains 2 classes of tests: unit and functional
- unit tests are written with pytest to directly call fastcov functions
- functional tests are black box tests executed by shell scripts against a CMake project