Add GMP to cmake
Use GMP
Add design.md
Implement addint and iaddint
Add the rest of functions
Remove operator-
Remove operator* and /
Remove operator-
Refactor operator+
Remove operator+
Remove operator-
Refactor mul
Remove operator*
Remove operator/
Remove operator<< for RCP
Implement pow and powint
Use pow()
Use pow()
Implement Integer.is_zero() and is_one()
Don't use "Integer->i"