Congruentie voorwaarden
Use all other fixes in https://github.com/Khan/khan-exercises/commit/83ab06dc30c3c2c21a36cf6b25d175f2ee89a3be
Fixes BH-390
Revert "Logo perceptum in footer"

This reverts commit 802329735ef342d33d49ccada8fb57c7a3d72f9a.
Fixes T22, 'The 5 badge mistake'
Add symbolic link for 'search' module
Enable the high replication datastore in the unit tests which is necessary for some tests in discussion.qa_test
Removed unnecessary import in make_test_db. fix_sys_path call is already done in tools/runtests.py
Added brackets around color to prevent it from messing up the shell
Removing fake_datetime replacements as these seem to be incompatible with the property validator in App Engine
Fixes the knowledgemap/layout_test unit test
Fixed helpus unit test. Videoless exercises belong to the Mathematics topics as defined in testutil/make_test_db
Fixes testutil.fake_datetime_test unit test

The standard fake_datetime is set on 2011 november 11 in the 'America/Los Angeles' timezone (Pacific Time)
There is no Daylight Savings Time observed at november 11 as this ended on november 6th in 2011.
This makes the time difference with UTC 8 hours instead of the suggested 7 in the test
See http://www.timeanddate.com/time/dst/2011.html and http://en.wikipedia.org/wiki/Pacific_Time_Zone
Changed all url_util_test unit tests to khanacademy.nl
Merge branch 'translation' into develop
Start "Vergelijkingen - Moderne Wiskunde" chapter exercises
Correctly generate question for 'Formules korter' exercise
Data-ensure at a single place
Use internal expressions library to represent equations
Add '=' as a commutative operator