Compatibility with version 0.5.3

[Philipp15b]

Hello,
node-jsonrpc does not really work with my nodejs version 0.5.3 for Windows. There were some errors while running this script.
(I´m diving into node and my solutions are try-and-error-solutions, so sorry for mistakes.)

HTTP Response methods renamed

The HTTP Response methods are now

• res.writeHead() instead of res.sendHeader(),
• res.write() instead of res.sendBody(),
• res.end() instead of res.finish()

Promises were removed in version 0.1.30

According to the release notes, promises were removed (https://github.com/joyent/node/wiki/ChangeLog , search for 'promise' or '0.1.30')

I didn´t make a fix for this so I could´nt find more incompatibilities, but I hope these are enough for now ;)