Fuzzing methods
Add some handy functions to flip bits and bytes in random positions inside octets, or at beginning or end, using xor or random values.
Based on the implementation of the Matasano challenge solutions, some others useful methods to have in Zenroom would be bitwise operations between octets, including AND, OR, and shift. Lua already implements these methods on integers, and it would be convenient to be able to do the same with zenroom.octet.
Please pay attention to indentation, in C it is tabs 8 spaces long
Waiting for @FilippoTrotter to complete it with deterministic state change checks: fuzzing should always change the contents of an octet and check the remote case in which random_bytes return same value or bitshift makes a full rotation.