Opcode generation isn't python3 compliant

[jconnor0426]

When using the latest version of yargen with python3 I found that opcodes were being added incorrectly. The opcodes included the python indicator for byte strings b'':

Example:

 $op0 = { b'595f5f5e5b8be55d51c3cccccccccccc' }

Likely due to an issue on this line not encoding the byte string as utf8:
https://github.com/Neo23x0/yarGen/blob/master/yarGen.py#L1641