Simplify several places

Simplify writing files
- Use with for file opening and autoclosing
- Remove urlsFull because it is needless duplication
Fix button packing to use list.append()
Fix style on a few lines
- Default arguments have no spaces around "="
- "+" should have spaces around it
Merge branch 'master' of https://github.com/powderblock/PyRSS

Conflicts:
	reader_tk.py