Add option for true color support

Add `let g:spacevim_enable_guicolors == 0` to `~/.local.vim` to disable
true colors.

autoload/SpaceVim.vim

@@ -24,6 +24,12 @@ let g:spacevim_default_indent          = 2
 " <
 let g:spacevim_max_column              = 120
 ""
+" Enable true color support in terminal.
+" >
+"   let g:spacevim_enable_guicolors = 1
+" <
+let g:spacevim_enable_guicolors = 1
+""
 " Enable/Disable google suggestion for neocomplete. by default it is Disabled.
 " you can enable it by:
 " >

config/general.vim

@@ -1,12 +1,12 @@
 scriptencoding utf-8
-exe "set wildignore+=" . g:spacevim_wildignore
+exe 'set wildignore+=' . g:spacevim_wildignore
 " shell
 if has('filterpipe')
     set noshelltemp
 endif
 filetype plugin indent on
 syntax on
-if count(g:spacevim_plugin_groups, 'colorscheme')&&g:spacevim_colorscheme!='' "{{{
+if count(g:spacevim_plugin_groups, 'colorscheme') && g:spacevim_colorscheme !=# '' "{{{
     set background=dark
     try
         exec 'colorscheme '. g:spacevim_colorscheme
@@ -20,11 +20,13 @@ endif
 if g:spacevim_enable_cursorcolumn == 1
     set cursorcolumn                "显示当前列
 endif
-if g:spacevim_hiddenfileinfo == 1 && has("patch-7.4.1570")
+if g:spacevim_hiddenfileinfo == 1 && has('patch-7.4.1570')
     set shortmess=filnxtToOFs
 endif
-if exists('+termguicolors')
-    set termguicolors
-elseif exists('+guicolors')
-    set guicolors
+if g:spacevim_enable_guicolors == 1
+    if exists('+termguicolors')
+        set termguicolors
+    elseif exists('+guicolors')
+        set guicolors
+    endif
 endif

doc/SpaceVim.txt

@@ -32,6 +32,12 @@ Change the max column of SpaceVim, default is 120.
   let g:spacevim_max_column = 120
 <
 
+                                                 *g:spacevim_enable_guicolors*
+Enable true color support in terminal.
+>
+  let g:spacevim_enable_guicolors = 1
+<
+
                                              *g:spacevim_enable_googlesuggest*
 Enable/Disable google suggestion for neocomplete. by default it is Disabled.
 you can enable it by: