initial set of performance improvements

[JRJurman]

Summary

• Removes querySelectorAll and uses TreeWalkers instead
• names previously anonymous functions so that they appear in the performance debugger
• Fix an issue with reseting scroll position on elements that have none

Changes to improve the performance throughout the framework. See the PR comments for more details!

Checklist

• [x] PR Summary
• [x] Tests
• [x] Version Bump