Updating gems

This updates all gems to latest available version.
Improves logging

This improves logging, by standardizing it via the `to_i` and `to_s`
methods.
Add modernizr to precompilation

This will precompile modernizr, and still allow it to be included
outside application.js
Upgrade to ruby 2.1.1
Don't run all specs after pass
Cleans up the available_characters method
Creates a separate AvailableFeats class

This class extends Enumerator and the Forwardable module, allowing
direct iteration across it.

This replaces the previous Feat.available_to method, and is responsible
for building a collection of feats available to the character.
Improve character index view
Remove flash on redirect

Caught exceptions from the levelup process is caught and displayed in a
flash. This patch ensures that the flash is ephemeral and won’t persist
when resolution causes a redirect.
Improves AvailableFeats and Feat documentation