Small improvements

Change backups and swap to save in central dir
Change j/k (gj/gk) maps to work with counts
Set *.md files to be markdown filetypes
Add directory creation for ViM

.vimrc changed backup behavior; this creates those dirs.
Change Airline Section Y

Change Airline_Y to percent usually
When a text-y file, add in wordcount.
TODO: change back when not a text-y file.
Generalize WordCount() to Count() bytes and words

Also clean up a few comments, etc.