Ignore close callback when closed.

This fixes a bug where closing a bullet
connection in poll mode will not work.
Fix jshint warning.
Drop reference to xhr request when done.
Add buttons to demonstrate sending for all bullet connections.
Use xhr for sending with eventsource connections.
Merge branch 'eventsource-xhr-send' of git://github.com/jdavisp3/bullet
Fixed error using undefined variable "fake".
Update README.
Merge branch 'master' of git://github.com/k2informatics/bullet
When polling check if data is defined

Prevent a javascript error that could stop polling. This happens
when a request returns a 204 No Content. jQuery success callback
has no data in this case causing an error.
Merge branch 'readme' of git://github.com/jdavisp3/bullet
Merge branch 'fix-jquery-ajax-when-data-undefined' of git://github.com/emb/bullet
 Fix undefined object error on IE
Update erlang.mk
Make Bullet work with Cowboy 0.9.0
Update erlang.mk
Update erlang.mk again
Merge branch 'fix-ie' of git://github.com/n11/bullet
Merge remote-tracking branch 'parent/master'