Allow operations with float values for int data type

[heinezen]

Currently, the int data type operations only allow integers as operands. This limits operations on int members somewhat, especially for multiplications.

int operations other than = should also allow floats to be used as operands. The result of the operation should be typecast internally to int, i.e. the resulting value is floored.

SomeObject():
    member : int = 4
    other_member : int = 9

Patch<SomeObject>():
    member *= 2.5f       # result: member = 10  (multiplication: 4 * 2.5 = 10.0 -> 10)
    other_member *= 1.5f # result: c = 13       (multiplication: 9 * 1.5 = 13.5 -> 13)

[TheJJ]

Done in #87.