add themes

Added the following themes: stekene dark/light, obsidian, tangotango
setup-themes.el: change default theme to obsidian
ignore emacs lockfiles and backup files

Also added setup-mail.el (pesronal information) and ac-dict
setup jedi for python
install new packages

init.el: sort package list
init.el: add mu4e, twittering, gist, esup, and nlinum
site-lisp: add mu4e package files
add new org-capture template for commit notes

For some repositories (especially this one), I make quite a few changes
before committing. So I've added an org template so I can quickly make
detailed notes of changes I've made and review them when I get around to
committing various changes and pushing them to remote.
modify keybindings

keybindings.el: Remove incremental search rebindings. It turns out I
rarely ever want to actually use regex in a search. When I do want to
use regex it's for search and replace and not incremental search.
keybindings.el: To remap insert, use global-unset-key rather than
global-set-key ... nil
keybindings.el: Add keybinding for spotify-previous