Update guard related gems

This is an attempt to solve the problem of guard intermittently loosing
file-save tracking, resulting in no tests running when files are saved.
Use reorder instead of order

This uses the new rails reorder method, instead of the old rails order
method.
Implement recursive feat lookup

This allows to call Feat#available_to supplying a character, and get a
collection of feats, which are available to that character, back.

This makes use of the closure_tree gem, to make feat hierarchy.
Display feat selection.

This constructs the html template, which will allow the user to select
feats to add to the character.
Improve Feat.available_to method
Add logger