[minor] Added an npmignore to keep the package size small
[fix] Simular to #117 but this completely disables the use of the xdomainrequest

1. It does not work from http to https
2. It's unable to send auth information such as cookies or basic auth headers
3. Can close connections when clicking on an url
4. Only allows plain/text
5. AND MORE ISSUES.
[minor] Wrap library code in a closure
[fix] Corrected the requirejs inheritance.

Fixes cayasso/primus-emitter#14 cc @ruimarinho
[minor] Less throws, more emits.
[major] Make private properties readable on the spark
[minor] Re-use the extend method of `predefine`
[minor] Set global context
[major] Introduce a new event, `readyStateChange` which will be emitted on each change
[fix] Remove Engine.IO memory leak