Added homepage, made minor visual adjustments to the skill tree page.

templates/Home.html
	-Homepage Jinja2 template. Only checks for logged in user, and displays a different message if there is one.

template/SkillTree.html
	-Title now links to website root

css/main.css
	-added rules to style the homepage
	-added extra definitions for cross-browser gradient support for the skill tree top panel

skilltree.css
	-.semester DIVs now have a fixed height

home.py
	-MainHandler complete with Home template integration

scripts/script.js
	-added global constant values for TOP and LEFT spacing for the .moduleBoxes.
	-Adjusted the positioning values for the .moduleBoxes, so they should align properly now.