Fix for messed up vim rendering when returning from <Leader>vv with EasyGrepCommand set to 1.

Additional info:
When using EasyGrep with EasyGrepCommand set to 1, the rendering of vim (i.e. font andbackground colors) is all messy when it returns from the bash shell
into vim. For example:
before <Leader>vv https://dl.dropboxusercontent.com/u/4664802/easygrep-before.png
after <Leader>vv https://dl.dropboxusercontent.com/u/4664802/easygrep-issue.png
redraw! (exclimation mark is important) fixed this

Note that this issue is actually mentioned in :help silent:
*":silent" will also avoid the hit-enter prompt.  When using this for
an external command, this may cause the	screen to be messed up.  Use
|CTRL-L| to clean it up then.*