[svn ci] Make PackFile_unpack just unpack, not fixup

Hi,

I just checked in a change to make PackFile_unpack only unpack, not fixup 
the packfile. When writing code that wants to deal with PBC files, sometimes 
we want the raw bytecode before it has offsets replaced with memory 
addresses (I'm currently writing pbc_merge, which has this need). I changed 
the few bits of code that used PackFile_unpack to also call fixup_subs 
afterwards.

For anyone wondering, pbc_merge isn't all that far along at all - this is 
just an early issue I ran into that needed fixing up before I could really 
dig into it.  I'll monkey on.  :-)

Jonathan 

• [svn ci] Make PackFile_unpack just unpack, not fixup by Jonathan Worthington