Make Query Helper more accessable

Record the int indices to convert in a class level variable; import
Query Helper by default
Add default index
Show index by default
Remove custom route for refactored api
Remove other functions in Courses controller

Move them to a special helper to reduce congestion of code in the
controller
Import Query Helper by default
Add search helper
Remove $this references
Change to singular result
Change from array to stdClass
Change CourseTime to Course
Update search by subject/level
Update courses to work without a value
Move search to search path
Remove parameter from handle_course_search
Add get_from_crn to Course model
Re-add class_id field to Course model
Add get by id function to Course model
Update routes and index in Courses controller
Reduce redundancy in Course model