Batch of improvements and bug fixes

[sam-github]

• Whitespace cleanup, terminate all lines with a NL
• Fix unsubscribe(), it was modifying its header argument
• Fix race condition between UNSUBSCRIBE and MESSAGE
• Pass an Error object to the error callback
• Use EventEmiter to manage list of error callbacks
• Fix argument order of subscribe, so callback is last
• Allow message headers to be specified on publish
• Fix error when no disconnected callback passed
• Return this so stomp methods can be chained
• Correctly end the TCP connection
• Fix errors caused by calling a null function
• Fix connect test, which was passing an options object
• Set default STOMP port to the common value

Which closes easternbloc/node-stomp-client#6

I have API docs coming, and might need to look at issues #4 by @bgraves, it looks real, and I also suspect problems if message headers contain NULs or newlines, or message bodies contain NULs, but there isn't unit test structure sufficient to reproduce.

[easternbloc]

Looks good cheers dude

[sam-github]

Thank you.