Wrote addFutureMeeting method. It now passes all tests.
Split testAddFutureMeeting test into three tests to ensure all exceptions are actually tested for.
Added a test for the getFutureMeeting method

Commented out the part of the test which can't run until the addNewPastMeeting method has been written.
Wrote getFutureMeeting method to pass all tests.

I noticed some typos in the comments on the interface for this method. I have written the implementation of this method as I interoperated it should be. I have changed the comments on the interface accordingly.
Added updated comments as mentioned in last commit

Forgot to add updated comments in last commit, have now done so.