#15 adding unit tests for `towardsHome` and `towardsAway`

Adding unit tests for the Board View that test the functions
`towardsHome` and `towardsAway`. To do so (and because it would be
benificial) I have the tested functions returning a line number where
the ball should be at. Also the `moveChip` function now calculates
based on an initial Y value and the current line number
#7 #15 renaming ball functions

renaming `towardsAway` to `ballTowardsAway`, `towardsHome` to
`ballTowardsHome`, and `moveChip(int)` to `ballMove()`
#7 #15 renaming changeChip to ballPosession

In the Board View, renaming `changeChip` to `ballPosession` and using
static variable identifiers. Also wrote Unit tests for the changes and
updated references in LevelOne
Merge pull request #16 from RedCardDev/dev-issue-15

Initial Unit Testing and Board View API improvements. Closes #7, Closes #15