MustParseGeneric is like ParseGeneric except that it panics on error.

MustParseSemantic is like ParseSemantic except that it panics on error.

ParseGeneric parses a "generic" version string.

ParseSemantic parses a version string that exactly obeys the syntax and semantics of the "Semantic Versioning" specification (http://semver.org/) (although it ignores leading and trailing whitespace, and allows the version to be preceded by "v").

Version is an opqaue representation of a version number.