Infrastructure in place for the display modes

Paired by Michael and Richard
Tests written for the DisplayMode object
Updated display mode tests. Paired by Richard and Michael.

The DisplayMode tests have been updated so that the display mode initialisation tests
will pass only if the mode's game engine stores the correct pattern. Additionally, the
tests partially pass due to part of the implmentation being written.
(Feature #175)
Merge branch 'develop' into feature/#175_Implement_mode_and_subclasses
Testing complete for the DisplayMode class. Paired by Richard and Michael.

All tests for the super DisplayMode class are complete and pass. (Feature #175)
Wrote skeleton framework for RunMode, ScreensaverMode and testing classes. Paired by Richard and Michael.

The classes for the above classes have been written but are currently unimplemented. (Feature #175)
Implemented the tests for "ScreenSaver"

Paired by Michael and Richard
ScreensaverMode has been implemented

Screensaver mode has been implemented. It cannot be visually tested until
the entire program has been implemented. All unit tests pass.
Paired by Michael and Richard
Tests for the RunMode have been written. Paired by Michael and Richard.

The RunMode testing class is complete, but all tests are currently failing because
there is no class implementation. (Feature #175)
RunMode completed. Paired by Michael and Richard.

The implementation of RunMode has been completed and cannot be tested further without
the physical display. However, all unit tests pass. (Feature #175)
Merge pull request #72 from CO600GOL/feature/#175_Implement_mode_and_subclasses

Feature/#175 implement mode and subclasses