Refactoring project and recent churn

 * In RebuildHistory, combined ProjectChurn and RecentChurn into one method.
 * Moved the ProjectChurn and RecentChurn classes over to their appropriate package.
 * Changed the property away from the timeline step (they can, and probably will be different)
 * Changed logger levels and formats to be more consistent with the rest of the system
 * Comments, whitespace cleanup throughout

This is related to issue #5