Improve XML Parsing Performance
Improve XML Parsing Performance

This roughly bumps the performance by roughly 4-8% by removing the
duplication checks for the xml attributes. This also gets rid of a lot
of allocations. Here's the performance comparison:

![https://i.imgur.com/SEU5kG5.png](https://i.imgur.com/SEU5kG5.png)

CryZe/livesplit-core,CryZe/livesplit-core