enable UUID for pbc

[rurban]

With r36890 I've enabled UUID stamping of pbc's for the t/native_pbc/ tests. tools/dev/pbc_header.pl --up works now again.

In order to enable UUID's (uuid_type=1) for all PBC's I plan the following:

• read the UUID, the md5 fingerprint of PBC_COMPAT with Parrot::BuildUtils::generate_pbc_fingerprint() at Configure.pl

• uuid_size = 12, so that the new padding in the header will be 2 instead of 14 and the header size before the directory stay the same.

• store the pbc_fingerprint as PBC_UUID in config.h for packfile.c

• write every pbc with this UUID

• check the UUID when reading pbc's and warn when reading incompatible PBC's, different UUID's.

• error on reading newer bytecode versions, allow reading older versions. That was the original intention at least.