v2.3.1

Bugs

• Fix broken coprocessor register access on ARM (#47).
• Fix broken coprocessor register access on ARM64 (#48).
• Fix broken MSR register write on x86 (#51).
• Correct MSR register reading on x86. It only worked before because the register ID was the first member of the struct used for reading/writing.
• Crash deterministically when attempting to access an X86 MSR with reg_read_batch(), reg_read_batch_as(), and reg_write_batch().
• Fix wrong hook function being called for CPUID. It wasn't being special-cased, meaning the normal instruction hook function was called. This returns void when Unicorn was expecting a boolean, so whether Unicorn fell back to using the default behavior was undefined.
• Crash with a better error message when attempting to hook CPUID on a version of Unicorn that doesn't support it.