Fix for: Basic support for :set statusline #1350

Hi Jared,

please review my fix. 

I add 2 new settings: 
* set laststatus=[Number] - 0 means off and some other value means on.
* set statusline=[Message] - Message will be, as it is, showed.  
Yep. The setting "statusline" is common for all buffers in Vim. 

Here an usecase for VS:
* Open 2 files (in tabs) 
* do `:set laststatus=2`
* do `:set statusline=Test`
* go to second tab
=> statusline is invisible without this code.

PS. While i wrote this comment, i found that this will not work perfect when i put both files side by side. But i have no idea how to fix it and i work rarely with side by side layout.