Add missing operations with unit tests

beembase\objects
* Amount improve handling of new appbase Amount format
beembase\operations
* Account_witness_proxy added
* Custom added
* Custom_binary added
* Prove_authority added
* Limit_order_create2 added
* Request_account_recovery added
* Recover_account added
* Escrow_transfer added
* Escrow_dispute added
* Escrow_release added
* Escrow_approve added
* Decline_voting_rights added
Unit tests
* add test_order_create2, test_witness_proxy, test_custom, test_request_account_recovery,  test_recover_account, test_escrow_transfer, test_escrow_dispute, test_escrow_release, test_escrow_approve, test_decline_voting_rights, test_delegate_vesting_shares, test_account_create_with_delegation added