Add motion aware send command

[christoomey]

Create a version of the run command that accepts motions. Default mapping would be gr, such that grip would run the current paragraph, grl would run the current line, etc.

This gets even better when you use custom text objects, like:

run this ruby method => grir

run the whole file => grae

run everything at this indentation => grii

[christoomey]

I've come around to thinking this is not desired. This is one of the cases where I really want the visual feedback of what I am about to send over and am ok trading away the slightly more direct motion based mapping.