Make builder.js perf warnings debug-only and info level instead of warn

These warnings can easily drown out everything else in the console, and they aren't relevant to most development
Change ABC parsing info to use console.info instead if console.time[End]

This spew is not interesting most of the time, so putting it in console.info to make hiding it easier
Merge pull request #882 from tschneidereit/master

Reduce spew from parser and builder