Add getStartPoint and isStartPointValid methods, refactor *FinishPoint methods

So we can cleanup the code in the Structures.
Get Sector timing to play nicely with Stage

This code adds the changes to ensure that the
sector timing will place nicely with stage tracks.

It also fixes up some broken unit tests and corner
cases that my changes exposed in the testing.
Add unit tests to the new track code.  Fix bug found.
Add unit test for stage sector.  Fix minor issues
Add core.* files to .gitignore

Because we never would want to check those in.
Refactor start/finish.  Fix bug for stage Track start line detection