No longer have special textured quad image, so changin this script - maybe should encapsulate all of demo.launch here.

Lookup most recent transform for the quad frame, not the now- this eliminates glitches in #3 and allows dynamic tf for #5

More consistent error handling - use throw catch everywhere instead of sporadic return falses. #5  Looks like the glitches in #3 are caused by a tf lookup problem

#2 roslint compliance and restructuring how image is updated for #3, but it didn't work- maybe that should be pre-render target instead?

#1 now can set tf from tf frame property, which makes this do everything I want it to.  However, I'd like to clean up the code a lot- I made a stashed attempt to get rid of the std::vectors, but the result was crashing.  Also I think the method of creating the quad and projecting the texture is not optimal, so that deserves some looking at.

#1 Eliminating the text node.  Seeing some rviz crashes, but was able to start a fresh rviz and get it working (where loading the saved rviz config wasn't working)

#2 roslint compliance, not finished yet but will probably not bother with remainder until other major changes are made.

Some changes necessary to work in qt5 kinetic, but others probably not necessary and should be separated out