[vim] use vim-unimpaired instead of custom mappings
[vim] group config by plugins
[vim] Disable completeJS and use term.js
[vim] remove tagbar config for scala (it's already in vim-scala)
[vim] remove unused stuff : taglist and dmenu
[vim] configure vim-scala for sorting imports
[vim] show arguments for js autocompletion
[vim] replace neocomplete with YCM