Support for TNS-strings

Adds support for TNS-strings like

	(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost)(PORT=MyPort)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=MyOracleSID)))

instead of using hostname + database. This should make it possible to connect to almost any oracle database, including all the features TNS brings.

Connect looks like this:

	var oracle = require("oracle");
	
	oracle.connect({
		"tns": "(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost)(PORT=MyPort)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=MyOracleSID)))",
		"user": "test",
		"password": "test"
	}, function(err, connection) {
		...
	}