Various fixes and a bit of cleanup

[calin-iorgulescu]

New features:

• Add config option to have students see only their own grades. TAs and Professors can be whitelisted to see all the results.
• websutil: Variable length fields for UserResults (useful for different length translations).
• GWT: Reset status bar on session timeout.
• GWT: Display both full canonical name and user name for current user.

Fixes:

• GWT: Properly highlight current user's submission when using LDAP.

Cleanup:

• config.py & confdefaults.py: Removed some redundant code.
• services.py: Dropped deprecated getResults() call. Split getAllGrades() code and move part into websutil.py .

[calin-iorgulescu]

Found bug in 737501c (reversed condition for getUserResults() ).

[calin-iorgulescu]

Added commit to fix aforementioned bug (814010e).