Add Vim's gf, <C-w>gf and <C-w>f commands

Hi, I added a new Normal binding map named 'fileEditBindings' containing the following bindings:

gf => open file name under cursor in the same window
Ctrl-w f => open file name under cursor in a new window
Ctrl-w gf => open file name under cursor in a new tab

It seems there isn't any infrastructure for testing impure bindings yet?