Ability to disable solarized enhancements [Fix #487]

doc/vim/enhancements.md

@@ -9,3 +9,7 @@
 * AnsiEsc - inteprets ansi color codes inside log files. great for looking at Rails logs
 * solarized - a color scheme scientifically calibrated for awesomeness (including skwp mods for ShowMarks)
 * Airline - Improved status bar. Requires patched fonts (installed from fonts/ directory)
+
+YADR provides solarized enhancements that make it even better. If you're using another theme, you can disable them with this line in `~/.vimrc.before`:
+
+    let g:yadr_disable_solarized_enhancements=1

vim/settings/solarized.vim

@@ -2,6 +2,7 @@ if !has("gui_macvim")
   set t_Co=256
 endif
 
+if !exists("g:yadr_disable_solarized_enhancements")
   hi! link txtBold Identifier
   hi! link zshVariableDef Identifier
   hi! link zshFunction Function
@@ -66,3 +67,4 @@ hi! EasyMotionTarget guifg=#4CE660 gui=bold
 
   " Make sure this file loads itself on top of any other color settings
   au VimEnter * so ~/.vim/settings/solarized.vim
+endif