Make sure web testcases all compile

testcases/graveyard/tutorials/01_Introduction.scala

testcases/graveyard/tutorials/02_Ex1_Account.scala

...ases/graveyard/tutorials/03_Ex2_Propositional_Logic.scala

testcases/graveyard/tutorials/04_Ex3_List.scala

testcases/graveyard/tutorials/05_Ex4_InsertionSort.scala

testcases/graveyard/tutorials/06_Ex5_Add.scala

testcases/graveyard/tutorials/07_Ex6_Mult.scala

testcases/graveyard/tutorials/08_Ex7_MaxSum.scala

testcases/graveyard/tutorials/09_Ex8_ListImp.scala

testcases/graveyard/tutorials/10_Ex9_RedBlackTree.scala

testcases/graveyard/tutorials/11_Ex10_SearchLinkedList.scala

testcases/web/demos/01_Compiler.scala

testcases/web/demos/05_OpenDays2.scala

testcases/web/sav15/02_Exercise2.scala