vim-nodejs-errorformat update

This is the first time I am requesting a new pull, so let me know if I missed something.

The error message generated by this code was not being parsed correctly:

function foo() {
    throw new Error('bar');
}
foo();

Nor this one: (this one generates a ReferenceError)

a[123456] = 123

Also I was not able to open the "native" files, not sure what might have changed recently but outputting with console.log works for me.

Tested in a Mac OS X 10.8.3

Change log:
Updated error format to parse ReferenceError
Fixed a bug when an exception was thrown in the "main" function
Fixed reading internal node files