added bakendconfig op

Which return the hash $config from Configure.pl.
write arrays as "key[i]=value" elements to config.c
map nqp::backendconfig in nqp-cc
rip out --cflags and --libs

Since we have nqp::backendconfig and therefore can let nqp do the hard work.
strip left-over pointer, pointed out by jnthn++
make config.c way more readable, jnthn++