Get a stage0 with extop support.

Bump really needed due to bytecode format change.
First pass at QAST->MAST extop updates.
Correct emit MAST::ExtOp where needed.
Pass MAST::ExtOp type to assembler.
Map nqp::settypecheckmode.
Map nqp::setdispatcher for MoarVM.

nqp::takedispatcher needs more work; it's not a straight mapping.
Map captureexistsnamed/capturehasnameds on MoarVM.
Merge branch 'master' into ext
Merge branch 'master' into ext
Fix MoarVM stage0; merge got us a bad one.
One Windows fix for NQP on MoarVM build.
Nananananananana BAT-var!