Some fixes for supporting python3

* Fix imports.
* Use python3 syntax.
* Wrap map() calls with list().
* Use list() only wherever needed.
  (Thanks Conley!)
* Fix dictionary iteration methods
  (s/iteritems/items/).
* Make use of sorted() in appropriate places
* Use iterators directly in the loop.
* Don't use .keys() wherever it isn't needed.
* Use sys.maxsize instead of sys.maxint

TODO:
* Make repo work fully with python3. :)

Some of this was done by the '2to3' tool [1], by
applying the needed fixes in a way that doesn't
break compatibility with python2.

Links:
[1]: http://docs.python.org/2/library/2to3.html

Change-Id: Ibdf3bf9a530d716db905733cb9bfef83a48820f7
Signed-off-by: Chirayu Desai <cdesai@cyanogenmod.org>

subcmds/overview.py

@@ -42,7 +42,7 @@ are displayed.
     all_branches = []
     for project in self.GetProjects(args):
       br = [project.GetUploadableBranch(x)
-            for x in project.GetBranches().keys()]
+            for x in project.GetBranches()]
       br = [x for x in br if x]
       if opt.current_branch:
         br = [x for x in br if x.name == project.CurrentBranch]