factor out the url handling from httprepo
Create url.py to handle all the url handling:
- proxy handling
- workaround various python bugs
- handle username/password embedded in the url
adding ab renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3a renamed from b:9a263dd772e0159ddfa70fb8a448bb6c7ec8c69f% test with --revb renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3