Better mappings for semi-colon key

- By default, map ';' to ':'
- Use original ';' (repeat 'f' or 't') functionality on double-tap of
  ';'
- Use original ',' (repeat 'F' or 'T') functionality on double-tap of
  ':'
vimrc updates

- Go back to dark theme
- Highlight cursor line & column
- Show line number for current line on left-hand side instead of
  relative line
Add new vundles