Expose inequality support in package metadata

[jheiss]

Packages currently can express dependency versions via min/max version, min/max package version, and allowed versions. Recently in order to support inequality on the command line (tpkg -i ruby>=1.9 for example) I added version greater/less than and package version greater/less than support to the tpkg library. We should expose that functionality in package metadata so that packages can express their dependencies using that functionality. gem2tpkg in particular needs this to properly translate gem dependencies to tpkg dependencies, it currently uses crappy workarounds.

Was: https://sourceforge.net/apps/trac/tpkg/ticket/45