Fix acceptance and unit tests

LMS-1296

LMS-2565

Also the idash_mode property is stored seperately for each course.

LMS-2565

RFC 2822 states that line lengths in emails must be less than 998.
Some MTA's add newlines to messages if any line exceeds a certain
limit (the exact limit varies). Sendmail goes so far as to add
'!\n' after the 990th character in a line. To ensure that bulk
mail messages look consistent long lines are wrapped to a
conservative length.

LMS-1466

STUD-1151

fixing unit tests

fixing merge error

fixing xqueue submission issue with unicode url (trial 0.1)

fixing fotmats as commented upon

removing yaml file language selection

Unicode changes to support QRF

removed unnecessary pass in modulestore/init.py

fixing merge error

fixing fotmats as commented upon

removing yaml file language selection

fixing pep8 violations

- fixing pylint violations

pylint violation

fixing line spaces and formats

ignore pylint E1101

remove empty line

fixing pylint violations

 pep8 violations

bulk mail unicode/decode

fix migration error

fix pep8 just to push again

more unicode/decode
Final changes to comments and error messages.

LMS-2134

STUD-1006

This centralizes the logic for group membership, and means that we
don't need to make queries to find out whether the legacy groups names exist.

Add cache-based locking to subtasks to ensure that the same task is not running in two workers at the same time.

Add cache-based locking to subtasks to ensure that the same task is not running in two workers at the same time.