[Caja] Dispose of caja.HostTools distinction

[Kevin Reid]

MarkM asked me to mention this explicitly regarding the eventual  
project of converting caja.js pretty interface over to the ES5/3 world:

I do not think the distinction between the 'caja' and 'caja.hostTools'  
objects was a good idea or is worth preserving.

--
Kevin Reid                                  <http://switchb.org/kpreid/>