Use a sequential numbering system instead of timestamps. This makes the
buffer names shorter and neater and easier on the eye when using
:NERDTreeMirror

remove "top" and "bottom" as valid settings for NERDTreeWinPos

previously, it wasnt highlighting the leading non-alphanumeric bits of RO files like   _foo.bar

Do an unlet <old key> when over riding a method on a prototype object.
Some older versions of vim spaz out otherwise.

Note: i was using these unlets up until a few versions ago when the were
refactored out

to TreeFileNode#findOpenDirSiblingWithVisibleChildren

move the bookmark validation logic into the model, as well as the
bookmark to root code