Reworked semester interactivity and added ability to mark modules as exceptions

templates/SkillTree.html
	-semesters are no longer stored within the skillTree DIV. Instead, they are now stored within a separate semesters DIV which is a sibling of the skillTree and resides in skillTreeView.

scripts/skillTree.js
	-code now updated to reflect structural change in SkillTree.html
Merge branch 'master' of github.com:TheFuzzy/ModuleSkillTree