Fix GoBuild for paths with spaces (fatih/vim-go#243)
Quoting path arguments for GoRun and GoInstall as well
Get GoRun to display output on Windows. makeprg only displays output on unices.

Should address fatih/vim-go#153
Merge pull request #244 from alexaandru/243-paths-with-spaces

Fix GoBuild for paths with spaces (fatih/vim-go#243)