Adding new validation rules for orders and drugOrders.

 - Null check for careSetting & encounter field.
 - Null check for drug in drugOrders
 - Null check for dose, dose units, route, frequency for drugOrders with SIMPLE dosingType
 - Null check for instructions for  drugOrders with FREE_TEXT dosingType
 - Null check for dosing_instructions for drugOrders for any other dosingType.
 - Null check for quantity, quantity units, and number of refills for drugOrders with outpatient careSettings.

It takes care of simple validation rules as defined in https://wiki.openmrs.org/display/projects/Validating+Orders . More validations will be added as subsequent commits.

Fixed tests failing due to these new validations. Fixed standardTestData.xml to create orders which honour these validations.

Removing voiding/unvoiding of Orders & Obs from patient void/unvoid handler.
These are automatically voided/unvoided in RequiredDataAdvice. Had to remove to fix some failing tests.