Store FCEs for the past year instead of just the past semester. Show separate FCEs for summer and non-summer semesters

[gramliu]

The FCEs when looking at courses for Spring while in Fall are very inflated since CMUnits draws from the summer semester FCEs. This can make it pretty hard for people to estimate their future course load. I'd recommend storing FCEs for the past school year instead of just the last semester. Then, the FCEs displayed can be based on what the next semester is, e.g. if it's currently Fall, show Spring FCEs.