Refactored parseAttrs

Moved parseAttrs from GlusterFileChannel to GlusterFileAttributes. Made it a static method to enable its use in GFChannel. Modified the unit tests for GFAttributes and GFChannel to reflect this refactoring.
We generally only put comments in for lines that we're unsure of so that when you're looking through the code, the lines will stand out. We should probably utilize GitHub's commenting system more for that purpose, though.