Prepare for the 6.1.0 release
Add utility <podextract.pl>, which uses only the internals of perldoc required to extract pod from a source file
config/gen/makefiles/docs.in: Universally invoke podextract.pl instead of perldoc
config/gen/makefiles/root.in: Add PODEXTRACT command for other things to use
config/auto/perldoc.pm: always call podextract in generated makefiles
[doc] improve intro.pod

changed #parrot irc server to MagNET (perl)
ChangeLog for podextract.pl GH #1028
[doc] add make installable to release manager guide

make docs is needed before make html to generate the ops pods.
disable not-existing tools/dev/mk_packfile_pbc
update tools/release/auto_release.pl accordingly
bump release 6.1.0
update t/native_pbc, add missing number_8_8_le.pbc

also speed up tools/dev/mk_native_pbc a bit.
just 4_be (powerpc) missing
[doc] update native_pbc instructions and tools/release/auto_release.pl

do not fingerprint unreadable old pbc files
make clear when just to fingerprint and when to regenerate