Immutabilize main object:

This speeds stuff up.
No need to eval LWP::UserAgent:

This would be useful to lazy-load it, but because there's already
a "use" statement at the top, it's already loaded by that time.
Conform to X.YYYZZZ version number:

Version numbers suck. They suck bad.

X.YYYZZZ is probably the easiest to work with. It allows SemVer,
it supports the issues with Perl version number notation(s).
Merge pull request #1 from xsawyerx/cleanups

Cleanups