Added a command to display UIImages them on the Mac client

Hi Jason,

I just added a command to transfer UIImages over JSTP and display them on the Mac client.

You can try:
.self
.image UIImage imageNamed:'Default'
.image self view generateImage
.image self redView generateImage

What do you think?

PS: the inclusion of NSData+Base64 should be done as a submodule, but as I think CocoaPods would be a better choice, I'll let you decide how to do this :-p).

PS2: this was really fun to implement! :-D

PS3: this time I forked the right repo… :-/