Add validity checker
Merge branch 'master' into GUI

Conflicts:
	DegreePlanner/DegreePlanner/Form1.Designer.cs
	DegreePlanner/DegreePlanner/Form1.cs
Merge branch 'GUI' of https://github.com/Belltron/431DegreePlanner into GUI

Conflicts:
	DegreePlanner/DegreePlanner/Course.cs
	DegreePlanner/DegreePlanner/Form1.Designer.cs