.vimrc: Add relative line numbers and hlsearch

.vimrc

@@ -14,7 +14,7 @@ if filereadable(expand(vundle_dir) . "/README.md")
     Plugin 'jeetsukumaran/vim-buffergator'
     Plugin 'ericcurtin/CurtineIncSw.vim'
     Plugin 'tpope/vim-fugitive'
-    " Plugin 'tpope/vim-surround'
+    Plugin 'tpope/vim-surround'
     Plugin 'ctrlpvim/ctrlp.vim'
     " Plugin 'shougo/neocomplete'
     Plugin 'godlygeek/tabular'
@@ -34,7 +34,15 @@ set shiftwidth=4 " when indenting with '>', use 4 spaces width
 set expandtab " On pressing tab, insert 4 spaces
 
 set mouse=a
-set nu
+set hlsearch
+
+" Hybrid line numbers on active buffer
+set nu rnu
+augroup numbertoggle
+  autocmd!
+  autocmd BufEnter,FocusGained,InsertLeave * set rnu 
+  autocmd BufLeave,FocusLost,InsertEnter   * set nornu
+augroup END
 
 " define upper case versions of :w and :q
 command! -bang -range=% -complete=file -nargs=* W <line1>,<line2>write<bang> <args>