remove inferno (bug TBD)

Inferno is out of date, and is a duplicate for the package build system we have. We actually have three build systems now:

- inferno
- Makefile (```make package```)
- gulp 

[gulp](https://github.com/mozilla/fireplace/pull/753) will win out. And fabric already bumps the newest version of the package on dev.

There is also some updates to the README that had some outdated stuff. Though I am going to write complete frontend docs on sphinx.
okay, maybe people don't need to know that the tests break with an older version. hopefully, people never try that. not sure why though. so point taken.