Add plugins to vimrc and update make_sym_links script

Vimrc:
- Add fugitive plugin
- Add tagbar plugin
- Add supertab plugin
- Add javascript plugin
- Reformat status line to increase readability and add git status
- Add keymap for TagbarToggle <leader>tb
- Add keymap for split window vertically <leader>sv
- Add keymap for split window horizontally <leader>sh

make_sym_links:
- Add the option to automatically install exuberant-ctags.
  The tagbar plugin requires exuberant user is now asked if they
  want to install.