Add ay2014to2015sem2 definitions; remove ay2013to2014sem2
Add ay2014to2015sem2 definitions; remove ay2013to2014sem2

nusmodifications/nusmods-api,nusmodifications/nusmods,nusmodifications/nusmods,nusmodifications/nusmods-api,nusmodifications/nusmods,nusmodifications/nusmods