Add support to normalize versions and dependency requirements

[pombredanne]

It would help to be able to compare and sort package versions and normalize version requirements from a package dependency (and in that later case to some mostly universal representation).

[pombredanne]

Some pointers:

From @jayvdb see:

• Parse version specifications gemfileparser/gemfileparser#6 (comment)
• Support other languages DanielVenturini/vigilant-lamp#3
• Parse version specifications gemfileparser/gemfileparser#6
• Support for various comparitors and range syntax rbarrois/python-semanticversion#73
• Regression and/or documentation lackage: cannot parse version from rubygems index d9pouces/RubyMarshal#3 (comment)
• https://github.com/mswart/debler/blob/c3ff2165d155ff3c10446d8f4de62ebc922094c7/debler/bundler/builder.py
• https://github.com/mswart/debler/blob/c3ff2165d155ff3c10446d8f4de62ebc922094c7/debler/bundler/parser.py
• https://github.com/coi-gov-pl/puppeter/blob/04e2a2008bd89a0429b734fdde6da83813688865/puppeter/domain/model/gemrequirement.py#L98
• https://github.com/sassoftware/python-rpm-vercmp

[pombredanne]

I also have debian version supported in https://github.com/nexB/debut/blob/master/src/debut/version.py

[pombredanne]

See also @jayvdb and @coala https://gitlab.com/coala/package_manager

[pombredanne]

And of course also @AMDmi3 https://github.com/repology/libversion and its postgres buddy