Better approach to versions.smackspec

[robsimmons]

as magenbluten says in comments to #15, the $SMACKAGE_HOME/versions.smackspec could become the victim of catastrophic success.

one a side note i would like to see a switch to sqlite (or say sql in general) for keeping the repo index. the txt file storage will become inefficient if more queries are to be made and more packages get added...

This is worth keeping in mind, though the time it takes to do ~1000 "git ls-remote" will be a problem long before the time or space that it takes to store 100 versions of 1000 packages becomes noticeable to the user.

[gian]

Yeah, I'm happy to run the risk that we might need to rewrite the version index code when we get to having thousands of packages. In the meantime I'd prefer to not introduce another dependency (or any non-text file solution) to solve a problem we don't have yet.