Util: now it requires perl v5.8.0 instead of v5.10.0. "sort" pragma requires v5.8.0. (reported by NEILB gh #6).
Total minimum version in cpanfile is also downgraded.
In addition, I added 'use v5.8.0;' to all modules because 'utf8' pragma requires that version, and I use the pragma so casually.