Added basic support for using Redis engine.

Currently PrivatePub does not allow Redis engine to be specified when initializing the Faye server.
Developers can now create a private_pub_redis.yml where desired values can be specified as per:
http://faye.jcoglan.com/ruby/engines.html

This commit does not include checks for required fields or conflicts between using socket or non-socket approach.
Added configuration instruction for Redis engine
fixed mount point
Refactor - Redis options are now passed into PrivatePub.faye_app.

@default_options is what we have today for specifying mount point etc.  But this can be changed to configurable as well.
Added some debugging
Changing how redis config is loaded
Setting default rails_env to be development
Increased timeout to 60
Fixed faye version to be 0.7.1 because thin was removed in a later version
Only sign when PrivatePub is avaiable.  When thin server is down, PrivatePub is undefined and client will get an error on not able to accessing faye.js.
Added logic to check in Faye server is up.  Only subscribe when it is up.  Log a console error if it is not.  PrivatePub client now no longer throw uncaught exception and upon seeing console log error, client can choose to handle the situation by performing a null check on PrivatePub.fayeClient.
Revert "Added logic to check in Faye server is up.  Only subscribe when it is up.  Log a console error if it is not.  PrivatePub client now no longer throw uncaught exception and upon seeing console log error, client can choose to handle the situation by performing a null check on PrivatePub.fayeClient."

We are violating cross-domain security check by making ajax call to Faye server.

This reverts commit ff647fa0f47b1fa383604e71b2893fd116dcc7fb.
Added support to Faye 0.8.0.

Faye 0.8.0 contains two incompatible changes according to:
http://blog.jcoglan.com/2012/02/27/faye-0-8-the-refactoring/

Notably, his check-in allows users to specify one of the 3 support adapters through private_pub.yml.
The supported adapters are: thin (default), rainbows, and goliath
Actually merge redis options
Merge remote-tracking branch 'zlu/master'

Conflicts:
	README.md
	lib/private_pub.rb