Added sync support for application's models

It is conditional, so if rhoconnect-client extension is disabled in build.yml, fixture data will be used instead.

Let me know if you want a different approach to this, I wasn't even sure if we needed to support "no rhoconnect-client extension" in this app.  The existing implementation indicates yes.

EDIT: Sorry about the formatting noise.  You can see the important parts of the diff by adding "?w=0" to the url:

https://github.com/rhomobile/rho-samples/pull/1/files?w=0