Library to read go coverage data programmatically

Because I want coverage information at runtime. go API's are closed and the tools repo has not been updated with the new coverage data structures.

Credit to the go team, I reused most of their code (internal/coverage) and defined wrapper data structures.

Tightly coupled with the encoding format of the Coverage information. i.e. The go compiler version.

• Need to add a version check
• Merge and diff CoverageData