[Ethereum] Solidity, how can I import struct mapping in contract A from contract B

You need to use an array in storage because it is not possible to resize memory arrays.

contract D { 
    uint[] myArray;
    function Test() constant returns (uint[]) {
       myArray.push(123); 
       return myArray;
    }
}

Otherwise you need to define the size of the array during initialization:

contract C {
    function f(uint len) {
        uint[] memory a = new uint[](7);
        bytes memory b = new bytes(len);
        // Here we have a.length == 7 and b.length == len
        a[6] = 8;
    }
}

Use

address payable public receiver;

in declaration for the addresses you are looking to transfer Ether in contract. As per the solidity documentation:

The address type comes in two flavours, which are largely identical:

address: Holds a 20 byte value (size of an Ethereum address).

address payable: Same as address, but with the additional members transfer and send. The idea behind this distinction is that address payable is an address you can send Ether to, while a plain address cannot be sent Ether.