Add uthread->state for debugging

Add state to the uthreads to make srue they are not restarted multiple times
by accident.
Initialize zeroth vcore last.

We do this last so that the pthreads that correspond to the vcores are
contiguous in GDB.
Set allocated to true before entering vcore trampoline

There was a slight race with this before (saw it lock up once) because we
never initialized allocated to true and were trying to allocate vcores before
they were ready.
Fix up some white space and tab vs space nonsense