fix(common): Adopt semver formatted version strings.

Drop zero padding and format versions as described by the semver spec.
The terminology is a little awkward because we inherited the backwards
meaning of 'BUILD' and 'BRANCH' version identifiers but that the version
strings themselves conform to semver.

(This doesn't change the current version, that'll happen with our next
branch cut)
Merge pull request #29 from marineam/semver

fix(common): Adopt semver formatted version strings.