Native process WIP.
We need register context.
Work on deferring the thread updating mach exception propagation at thread update time instead of taking care of it at exception time.
Now, the thread update is driven by the Process class, and no longer managed by the NativeProcess layer.
Replacing int/uint32_t by lldb::RegisterKind.
Implements register info for darwin x86_64.

Why should we rewrite eat another one ?
- The existing LLDB implementation does not support AVX and pseudo registers.
- The DNB implementation supports AVX and pseudo register but uses debugserver specific types.
Work on register context and resume.
Fix issue when exec and new thread keep the same tid.
DoDetach stub.
Works on Halt, get Thread Name, Register Context save/restore…
remove dead ref
Project cleanup
Detach/Kill.
Exc register set is read only.
Thread::DidStop don't have to be part of the native thread protocol.