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>

main.py

@@ -50,6 +50,11 @@ from pager import RunPager
 
 from subcmds import all_commands
 
+try:
+  input = raw_input
+except NameError:
+  pass
+
 global_options = optparse.OptionParser(
                  usage="repo [-p|--paginate|--no-pager] COMMAND [ARGS]"
                  )
@@ -286,7 +291,7 @@ def _AddPasswordFromUserInput(handler, msg, req):
   if user is None:
     print(msg)
     try:
-      user = raw_input('User: ')
+      user = input('User: ')
       password = getpass.getpass()
     except KeyboardInterrupt:
       return