Update vimrc: add *.tex to formatting augroup
Fix vimrc: gitcommit formatting autocommand
Update vimrc: remove <leader>l mapping as is redundant

I removed the <leader>l mapping because we now use Unite.vim, which has
the capability of listing buffers much better than Vim does by default.
Update vimrc: remove LaTeX-Box plugin
Update vimrc: add latex mappings
Update vimrc: improve latex mappings
Merge branch 'no-latex-box' into dev

- Replaced LaTeX-Box plugin with a couple of key mappings:
  - <leader>lb: builds current .tex files
  - <leader>lv: opens up current resulting .pdf file with evince
  - <leader>lbv: builds current .tex file and opens resulting .pdf file
    with evince