Escrow Contract

It contains Escrow Contract implementation in Scilla.

References taken:
https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/payment/escrow/Escrow.sol

Test cases

1. primary: address of primary. Expected: [Success] 0x263c4ca003235af83c4f4bc065d00d4a67ffb617.
2. transferPrimary: transfer primary. Expected: [Success] .
3. depositsOf: deposits of the any payee . Expected: [Success]
4. deposit: deposit the deposits(_amount) to payee. Expected: [Success]
5. withdraw: withdraw all deposits from payee. Expected: [Success].
6. withdraw: withdraw all deposits from payee. Expected: Failure as the withdrawee _sender is not primary. Error: not primary.