made DownloadCommentsTest.java with some empty tests
wrote some simple code for testcases, still not finished
more detail added, still not complete
finish test case 4,4.1,4.1.1 not compilable, uses unimplemented code
fixed some errors, made up unimplemented DataManager class to handle saving and loading from file
simple fixes
fixed errors in assert statements
changed assert statements to use .contains()
fixed comments in last assertions
Merge pull request #31 from CMPUT301W14T13/TestCases3.1-3.3,4.1and4.1.1

Test cases3.1 3.3,4.1and4.1.1