Replace vim-gitgutter with vim-signify

vim-gitgutter is buggy. vim-signify might be better, it does allow
configuration of which events trigger a sign column update and this
patch takes advantage of that. Firstly, the `CursorHold` and
`CursorHoldI` events are disabled and replaced with `InsertLeave` and
`TextChanged` events. This makes the sign column updates immediate, and
since vim-signify is asynchronous it's faster too.

autoload/do.vim

@@ -69,7 +69,7 @@ function! do#rename_include_guard(old)
   call setpos('.', l:pos)
 endfunction
 
-" Setup and start a debugging command.
+" Setup and start a debugging command
 function! do#debug(...)
   packadd termdebug
   let l:command = 'TermdebugCommand'
@@ -86,3 +86,13 @@ function! do#last_change()
     norm!``
   endif
 endfunction
+
+" Augment vim-signify update events
+function! do#signify() abort
+  " Disable update on cursor hold
+  autocmd! signify CursorHold,CursorHoldI
+  " Enable updates on leaving insert mode
+  autocmd signify InsertLeave,TextChanged <buffer> call sy#start()
+  " Enable update on text change e.g. undo/redo
+  autocmd signify TextChanged <buffer> call sy#start()
+endfunction

colors/fresh.vim

@@ -207,5 +207,9 @@ if has('gui_running') || &t_Co == 256
   call s:hi('SyntasticWarningLine', '', '', '')
   call s:hi('SyntasticError', '160', '', '')
   call s:hi('SyntasticWarning', '129', '', '')
+
+  call s:hi('SignifySignAdd', '2', '233', '')
+  call s:hi('SignifySignChange', '3', '233', '')
+  call s:hi('SignifySignDelete', '1', '233', '')
   "" }}}
 endif

plugin/autocmds.vim

@@ -25,4 +25,7 @@ augroup benieAugroup
   au BufNewFile * silent! call snippet#template()
   " Do the same when filetype changes to help
   au FileType help silent! call snippet#template()
+
+  " Augment vim-signify by modifying it's autocmds
+  au User SignifyAutocmds call do#signify()
 augroup END

vimrc

@@ -68,12 +68,10 @@ let g:ale_linters = {'c': [], 'cpp': []}
 let g:ale_cmake_cmakelint_options =
       \ '-convention/filename,-package/consistency,-package/stdargs'
 
-" git diff in the sign column
-Pack 'airblade/vim-gitgutter'
+" Version control differences in the sign column
+Pack 'mhinz/vim-signify'
 if exists('&signcolumn')
   set signcolumn=yes
-else
-  let g:gitgutter_sign_column_always = 1
 endif
 
 " format.vim - format with text objects