Switch to line numbering available in Vim 7.4

Signed-off-by: Julio Espinoza-Sokal <julioes@gmail.com>
Remap ESC and leader

Signed-off-by: Julio Espinoza-Sokal <julioes@gmail.com>
Add spellcheck and shortcuts

Signed-off-by: Julio Espinoza-Sokal <julioes@gmail.com>
Remove key mapping for numbers bundle

Signed-off-by: Julio Espinoza-Sokal <julioes@gmail.com>