XPath queries do not work with namespaces and fixed encoding property

[rhodgkins]

Hello (again!)

I noticed that any XPath queries containing namespaces //ns1:tagname would fail with the error:

XPath error : Undefined namespace prefix
XPath error : Invalid expression

I've added a test case for this issue and the Travis build file to ensure the tests on my fork pass :)
https://travis-ci.org/rhodgkins/Ono/builds/26876794

[rhodgkins]

The fix registers any namespaces on the ONOXMLElement that is being queried. Any unprefixed namespaces (such as xmlns="http://www.w3.org/2005/Atom" in the atom.xml example) are ignored.
https://travis-ci.org/rhodgkins/Ono/builds/26877560

The only other issue I think might still exist is if there are any namespaces that are declared in nested elements - for example:

<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/elements/1.1/">
  <entry xmlns:nested="http://purl.org/dc/elements/1.1/">
    <nested:title>Atom-Powered Robots Run Amok</nested:title>
    <dc:language>en-us</dc:language>
  </entry>
</feed>

The nested namespace wouldn't be picked up if querying the root node for //nested:title. I'm not really sure if this is an actual use case or if its even possible to register all the namespaces without traversing the whole tree?

[rhodgkins]

Also fixed rhodgkins#1

[mattt]

Thanks so much for your help on this, @rhodgkins. This is excellent work. I'll tag a new release now.

[rhodgkins]

No problem @mattt, thanks for the great working creating this in the first place!