replaced group_default_instructor table with two separate join tables.
add migration for breaking up the group_default_instructor table.
bumped migration number.
bumped migration counter.
rewrote ALL the queries that were pulling data from group_default_instructor to use group_x_instructor/group_x_instructor_group as applicable.
replaced group_default_instructor with group_x_instructor_group in query.
replaced group_default_instructor with group_x_instuctor/group_x_instructor_group as applicable.
removed unused method deleteInstructorsForGroup().
replaced group_default_instructor with group_x_instructor_group.
switched the order of PCRS and program objectives in relationship output.
refactored SQL query in getQueryResultsForInstructorsForGroup() to use new join tables instead of group_default_instructor.
refactored saveInstructorsForGroup() to store group/instructor and group/instructor_group associations in separate join tables instead of group_default_instructor.
fixed typo in variable name.
Merge pull request #266 from stopfstedt/master

fixed typo in variable name.
Merge branch 'master' into feat211_replace_offering_instructor
replaced table offering_instructor with offering_x_instructor and offering_x_instructor_group.
replaced triggers on table offering_instructor with triggers on offering_x_instructor and offering_x_instructor_group.
bumped migration counter.
added migration for splitting up the offering_instructor table.
bumped migration counter.