Remove memcache and change from db to ndb

First commit in this branch
Remove cache & replace db with ndb: photo upload

fixed photo upload class
Some more ndb changes
Version increment

Major change from db to ndb and removing memcache.
Model field names: remove '_key'

Some fields were renamed to 'foo_key' because ndb stores keys for
reference objects. But this caused a problem with online db - names
didn't match. So revert to old names.
Merge ndb and master branches
Competition selector on user page

Increased its width
Merge branch 'ndb-copy'

Conflicts:
	README.md
	competition.py
	handler.py
	main.py
	photo.py
	templates/competition-scoring.html
	test.py