Make Renderer aware of block metadata

Different block data can be mapped to a different color.
Used this to render colored wool.
Fix misspelling of "r" as "w" to 'Actually open region files in read-only mode.'
Some refactoring around UltraPeeks' changes.
Have ColorMap.load report bad lines instead of crashing, and fix block-colors.txt to not crash it.
Allow specifying multiple region files or directories and track (and report, if -debug) processing time for various things.