Trim tailing spaces is a function; list chars defined globally

The regexp used to removed the tailing spaces at the end of lines is now
a function, so it's easier to use it in autocommands.

Also, moved the list chars outside the C syntax auto-command, so we now
have a style that works globally. It's disabled globally too (nolist) so
each syntax can enable (or we can manually enable if needed).

configs/vimrc

@@ -58,6 +58,8 @@ set vb t_vb=            " convert bells to visual bells and do nothing as visual
 set t_Co=256			" 256 color terminals
 set modeline 			" Enable modelines
 set undofile			" saves undo changes in a separate file, so we can undo anytime
+set lcs=tab:¦\ 			" uses a special char at the start of a tab character, uses spaces after that
+set nolist				" ... but don't display them by default
 
 let mapleader=","     " use comma to start user-defined (in plugins) functions
 
@@ -176,22 +178,29 @@ set wildignore+=*/build/*,*.egginfo,*.pyc,*.mo,*/dist/*
 "  Auto-commands
 " ----------------------------------------------------------------------
 
+" Because most auto-commands add a "trim tailing spaces" regexp, we will
+" create a function to do that, so auto-commands can simply :call it.
+function TrimWhiteSpace()
+  %s/\s*$//
+  ''
+endfunction
+
 " default python style
 " (use spaces instead of tabs (expandtab), uses 4 spaces for tabs (tabstop),
 " when auto-indenting, also use 4 spaces (shiftwidth), when deleting text, 4
 " spaces are a tab (softtabstop) and break the line at column 78 (textwidth))
 " also, remove all tailing spaces
 au FileType python setlocal expandtab tabstop=4 shiftwidth=4 softtabstop=4 textwidth=78 colorcolumn=79
-au FileType python autocmd BufWritePre <buffer> :%s/\s\+$//e
+au FileType python autocmd BufWritePre * :call TrimWhiteSpace()
 
 " Default C/C++ style
 " show a column marker at column 100, break the line at line 100, use tabs
 " instead of sapces and display a "¦" for tabs (this way we can see the lines
 " that are not using real tabs)
-au FileType c setlocal colorcolumn=100 tw=100 noet list lcs=tab:¦\ 
-au FileType c autocmd BufWritePre <buffer> :%s/\s\+$//e
-au FileType cpp setlocal colorcolumn=100 tw=100 noet list lcs=tab:¦\ 
-au FileType cpp autocmd BufWritePre <buffer> :%s/\s\+$//e
+au FileType c setlocal colorcolumn=100 tw=100 noet list
+au FileType c autocmd BufWritePre * :call TrimWhiteSpace()
+au FileType cpp setlocal colorcolumn=100 tw=100 noet list
+au FileType cpp autocmd BufWritePre * :call TrimWhiteSpace()
 
 " Default ReStructured document style
 " reStructured files follow python closely, but use 3 tab stops instead of 4
@@ -238,14 +247,15 @@ au FileType javascript setlocal expandtab tabstop=2 sw=2 sts=2 textwidth=0
 let g:vim_json_syntax_conceal = 0
 autocmd BufNewFile,BufRead *.json set filetype=json
 autocmd Filetype json set et ts=4 sts=4
-autocmd FileType json autocmd BufWritePre <buffer> :%s/\s\+$//e
+autocmd FileType json autocmd BufWritePre * :call TrimWhiteSpace()
 
 " Default Pinpoint style
 au BufNewFile,BufRead *.pin set filetype=pinpoint
 au FileType pinpoint setlocal colorcolumn=79 textwidth=78
 
 " Default Yang style
-
+au FileType yang set et
+au FileType yang autocmd BufWritePre * :call TrimWhiteSpace()
 
 " ----------------------------------------------------------------------
 " mapings