wire up and use nqp::backendconfig

This is just lacking a fresh stage0 to work.
first pass at stat() docs.

Pulled solely from the JVM impl.
[parrot] fix race condition in the build

the dyncall ops depend on the basic nqp ops; this failed reliably for me
with make -j3
Merge branch 'master' into config
install nqp-on-moar as nqp-m
import NQP::Configure changes from Rakudo
Updated MoarVM stage0 for config info.
[Configure] implement --gen-moar
Merge branch 'config'
Merge branch 'master' of github.com:/perl6/nqp
[Configure] fix double quoting fail
Merge branch 'master' of github.com:/perl6/nqp
Use consistent grammar to parse subrule arguments.

This fixes the problem where <subrule(...)> could take any kind of arguments,
while <subrule: ...> only accepted a list of strings (and didn't interpolate
variables in double-quoted strings).

Closes #105.
Support --vmlibs on MoarVM.
Merge branch 'master' of https://github.com/perl6/nqp into stdsigspace