UI updates and backend bug fixes

data.py
	-Data class added, this will provide helper functions for commonly used datastore queries
	-error fixed in SaveSkillTreeHandler

modulescraper.py
	-logic added to handle modules with multiple codes (separated by " / "). Modules will be separated and have each other as preclusions

scripts/script.js
	-search and filter functions moved out of jQuery ready function
	-fixed errors with prerequisite groups
		-adding a module with an unfulfilled prereq did not move it to the 2nd semester automatically.
		-removing a prerequisite from the second semester caused a fatal error
	-addModuleToTree now properly unfilters the search panel before adding the module.