Bug fixes, bio:setup

Added code to initialize the examglobal entity in the database.

Fixed bugs:
1. The loops that found the total mean score would overwrite variables,
causing the points to be displayed incorrectly.
2. If the exam didn't exist it would try to continue anyways
3. If you had been assigned a grader who didn't grade, it would try to
add the null scores anyways.
4.The average loop didn't even compute the average…