Some performance tweaks [WIP]

As library used by another libraries, inflecto should work as fast as possible. Here is some performance tweaks i planned during previous PR. Results on ruby 2.1.3p242:

* tableize - (1.3-1.6x)
* ordinalize - (1.1-1.3x)
* uncountable? - (2x)

pluralize and singularize should work faster as well, because they use uncountable

Also this PR demonstrates my crazy naming skills, so feel free to suggest better names