Trunk-4444 Validate order overlap with scheduled date

Comments:
In Order.java:
          - getCalculatedStartDate and getCalculatedEndDate are kept public for future use.
          - Can rename getCalculatedEndDate and getCalculatedStartDate with better names (if any).
Same here, this is just returning an effective stop date and doing no calculation, i would rename it to getEffectiveStopDate(), so you can keep it public