Fully qualify imports.
Clearer syntax.
Return string from Util.getSourceCode.
Use hash keys in string formatting.
Alias urllib2 to urllib.request in 3.x.
Use assertTrue instead of assertGreater for compatibility with 2.5 and 2.6.
Convert bytes pattern to string.
Force explicit casting of image url to string.
Remove 2.5 testing from travis-ci.

2.5 doesn't have support for the abc module.
Match lazily in regexes.

This is to prevent inconsistent matching behavior in 2.x vs 3.x.