Edit distance scaling

[canweriotnow]

Make the max Levenshtein distance a function of the length of the method name... Possibly exclude common method prefixes (like to_ or even each_) from the calculation... At this point, excluding to_* methods (to keep RSpec working); this enhancement would replace this behaviour with edit distance scaling (with possible common prefix elimination).

This is mainly a duck typing issue... calling to_r in place of to_ary is a serious problem.