Integrated mockup with backend further, fixed bugs

UI is now as close to the prototype as it gets.

data.py
	-Fixed syntax error in GetModuleHandler

scripts/script.js
	-added a countModules method, as both the assignedModules and modules properties in the skillTree global variable are key/value pairs, which are essentially objects and not arrays in Javascript.
	-abstracted module loading to separate methods
		-isFullyLoaded checks that a module has been loaded from the server.
		-ensureModuleDetails loads a module fully from the server (if it hasn't been already), and optionally runs a callback, re-retrieving the module if necessary.
	-all for loops that involve the assignedModules global variable now have a conditional check whether the element it is accessing is its own property, so that it is accessed like a dict in python
	-Commented out recursive loading of prerequisites, will be replaced by user's choice functionality later
	-module list double click handler re-written with ensureModuleDetails integration.

scripts/skillTree.js
	-commented out endpoint styles, as endpoints are invisible.
	-uncommented connectorHoverStyle definition
	-added code to hide the connectors of a module as it is being dragged.
Added notification flash, fixed a few bugs

css/main.css
	-Added declaration for a .flash class for the #notification DIV

scripts/script.js
	-notify() will now flash the notification bar if it is already visible.
	-fixed undefined module bug from getModule() and getAssignedModule
	-added notification if user tries to move a module before semester 1.
	-when a module prerequisite group has 0 elements, the script pretends it was fulfilled anyway.
	-old recursive module prerequisite fulfillment logic now applies if there is only 1 module in a prerequisite group.
	-stub added for addModuleSelectionToTree method
	-disabled detection for dropping a module box outside a semester.
	-missed 2 for loop fixes from the last commit

scripts/skillTree.js
	-defined a new jQuery function moduleSelectBox, which initialises a module selection DIV