Get latest NQP and MoarVM improvements.
Modernize INSTALL.txt

Make MoarVM more prominent and make it match the install instructions in
README.md.
Update to new MAST::Label API.

Includes NQP_REVISION update, which also updated MOAR_REVISION.
handle Num case in blocks in quantifiers in regexes
handle the case where perl6 -Mfoo switches to a slang

In the common case where this is not the case it is just an istype check and
the call to LANG.
test S32-list/permutations.t
Remove dead code

Since we have CompUnitRepo objects living in @*INC, I don't see how this could
ever work.  Removal does not seem to break anything at all in spectesting.
Alas, this code is needed still

To correctly identify which directories were searched if a compunit load fails.

This reverts commit 22b0fec24548dcfd9b22231629637d4d3dc96158.