Introduce SemVer-compressed versions like "1.0" as valid

[techtonik]

Enhancements and Features

#855 proposes to count "1.0" as SemVer, but SemVer is a specification, so it will break the spec. Instead, SourceRank can introduce SemVer-compressed or SemV that is just shortened version, which allows to omit trailing .0. That is useful for small projects where "functionality in a backwards compatible manner" (MINOR) are rarely added and often is a part of "backwards compatible bug fixes" (PATCH).

SemV is just MAJOR.MINOR, where:

• MAJOR is incremented on incompatible API changes
• MINOR increment means new backwards compatible functionality or backwards compatible bug fixes