Breaking change between 0.2.2 and 0.3.0

[Redsandro]

There is a breaking change between xml2js-expat 0.2.2 and 0.3.0, although I can't quite put my finger on it.

Our app is breaking (throwing errors without a message property) using 0.3.0, but everything works fine again on 0.2.2.

It is hard to track down the problem, because it only happens on production (where there is a large amount of XML being parsed), and I can't recreate it in a safe development environment.

@Poetro any idea from doing the 0.3.0 rewrite where differences could be introduced? I haven't found realease notes specifying a specific area of notice when upgrading from 0.2.2 to 0.3.0.

If we could stick with 0.2.2 that would be okay, but we need 0.3.0 for node 10 support, or switch to an alternative xml processor.

[Poetro]

I changed the order of the arguments from

new xml2js.Parser(function(result, error)

to

var parser = new xml2js.Parser('UTF-8', function(error, result) {});

This is why I considered it a major version update according to semver.