Add library generator to resolve struct member pointers

[d1ll0n]

example:

struct Data {
  uint256 a;
  uint256[] arr;
}

library DataPointers {
  function Data_a_pointer(MemoryPointer mPtr) internal pure returns (MemoryPointer aPtr) {
     aPtr =  mPtr;
  }
  function Data_a_pointer(CalldataPointer mPtr) internal pure returns (CalldataPointer aPtr) {
      aPtr = mPtr;
   }
  function Data_arr_pointer(MemoryPointer mPtr) internal pure returns (MemoryPointer arrPtr) {
      arrPtr = mPtr.pptr(32);
  }
  function Data_arr_pointer(CalldataPointer mPtr) internal pure returns (CalldataPointer arrPtr) {
      arrPtr = mPtr.pptr(32);
  }
}