Edit contribution form: filter contribution status dropdown based on status change rules

Available contributions status options need to be filtered to only allow supported state changes.

1. Unset "In Progress" status for all conditions including New Contribution (create). This is only used for Pledges records.

2. Unset "Refunded" status for CREATE contribution (can't do a refund unless contribution already exists).

3. Unset "Overdue" status option for CREATE contribution. Unset 'Overdue' in UPDATE mode IF contribution is not linked to a pledge_payment (e.g. $this->_ppID not set).

4. Unset additional statuses in UPDATE mode as shown in this pseudocode:

switch($contributionStatus)

{ case 'Completed', 'Cancelled', 'Refunded' : unset all EXCEPT Completed, Cancelled, Refunded case 'Pending' : unset all EXCEPT Pending, Cancelled, Completed, Failed case 'Failed' : unset all EXCEPT Failed }

5. Verify the available state changes to the expected data flows on the wiki in this section and below:
http://wiki.civicrm.org/confluence/display/CRM/CiviAccounts+4.3+Data+Flow#CiviAccounts4.3DataFlow-RefundORCancelaCompletedcontribution%28changestatustoRefundedorCancelled%29