Spell-check Markdown by type, not file extension

Previously, only `*.md` files would get spell-checking. This change adds
`*.markdown` and decouples Markdown spell-checking by file extension.

http://robots.thoughtbot.com/vim-spell-checking/
Disable Rubygem documentation to make Bundler fast
Updates dotfiles to have .local files as needed

* in favor of the old way of #DO NOT EDIT BELOW THIS LINE, dot files
* were changed to have local config files - updates local dotfiles ot
* match this preferred pattern
Adds git plugin back for git branch auto completions
updates source path
Color and alias tweaks
Adds rspec mappings
Adding aliases
Small tweaks
Add rspec configuration
Adds Ag
Change from RVM to RBENV