Add Data option to push. 

* bump to v.1.5
* Since dev changed significantly, had to refactor #88 into this version

@kitcambridge r?
Oh yeah, I remember us talking about this. I'm actually fond of keeping reasonably tight constraints on the data we send through because I don't really want folks using this to send files or updates around. (Heck, I'd be thrilled if the "data" was under 1K.) 

Still, using something like MaxBytesReader might make more sense since we're specifying it upfront and defining the block of acceptable memory.