Parrot and Perl5 Embedding Repaired.

Now with extra import sugar for Perl 5:

use perl5:Digest::MD5 <md5_hex>;

# 09189568a8ee4d0addf53d2f6e4847cd
'pugs'.md5_hex.say;

Also, through some evil contortions, embedded Parrot now won't crash due to invalid PGE expressions. Hopefully some day Parrot can be embedded with multiple non-interfering instances, or maybe raise a proper exception instead of forcibly calling Parrot_exit on a PIR syntax error... But for now, evil contortions would have to do.

Next in sight: PGE adverb support, repair the JavaScript backend, README, and preflight!