added session-type/aamc-method mapping to db default population. fixed one broken session type title, removed an obsolete one and added another missing one. refs #3807
added migration for linking session types to AAMC methods. refs #3807
bumped migration counters.
completed session-type/aamc-method mapping for SOM. refs #3807
redefined primary key on session_type_x_aamc_method table.
replaced the value for <AssessmentMethod> and <InstructionalMethod> elements with AAMC method IDs. refs #3810
updated events query to include AAMC method ids rather than Ilios session type titles. refs #3810
Merge pull request #182 from stopfstedt/rb2.3

implemented Ilios session type to AAMC method mapping.