Compatibility with ud_opcode.py and Python 3.5

[Rudedog9d]

There is a TypeError Raised by the following code in ud_opcode.py when run in Python 3.5:
TypeError: %x format: an integer is required, not float

    for k, e in entries:
        if isinstance(e, UdOpcodeTable):
            self.log("%s    |-<%02x> %s" % (indent, k, e))
            printWalk(e, indent + "    |")
        elif isinstance(e, UdInsnDef):
            self.log("%s    |-<%02x> %s" % (indent, k, e))

Purposed fix: Typecast the float k to an integer. (self.log("%s |-<%02x> %s" % (indent, int(k), e)))

Would this cause problems? The built in function k.hex() could be used but this produces a string, which would then not be format-able.

[woodruffw]

This is also preventing mishegos, which fuzzes this project, from upgrading its environment: trailofbits/mishegos#1606 (comment)

[martindorey]

A second pull request that fixes this, in what's imo a less elegant way, is at 9c11d83. A third pull request that fixes this is in #139. That, imo, is the most elegant of the three, getting rid of the unnecessarily floating point numbers at the root of the issue. I confirm it's correct and complete.