0   - not used.  FZC should never generate it.
1   - no password found; finished
2   - one or more possible passwords found; finished
3   - found password; finished
4   - no password found; suspended
5   - one or more possible passwords found; suspended
6   - found password; suspended

NOTE: "suspended" means the user pressed ESC or some signal forced FZC
to save & exit, except when exitcode==6, because when FZC is sure it
found the correct password (see MinBitsToExit setting in FZC.CFG) it'll
force a save & exit.

7   - something wrong in command-line (9 and others might be reported as 7)
8   - can't open wordlist for read access
9   - wordlist empty
10  - no such starting line (invalid -f parameter)
11  - wordlist contains control characters
12  - resume file not found or invalid
13  - invalid charset length: must be 1<len<255
14  - not implemented (eg tried to use the template mode)

22  - FZC.CFG not found
23  - can't write to FZC.LOG - it's read-only or other session locked it
24  - can't create/open resume.fzc for write access
25  - not a ZIP, unknown sfx or badly damaged file
26  - seems to be a ZIP 1.xx archive
27  - no encrypted files found

51  - error in FZC.CFG
52  - unknown setting in FZC.CFG
53  - invalid value for setting in FZC.CFG
54  - redefining setting in FZC.CFG
55  - some settings missing in FZC.CFG

60  - (character set size)^2  <  number of machines used

1001 .. 1500 (now 1076) are internal errors.  They mean that something that
should not happen actually happened, like not being able to change priority
or close an open file, or that some routine received or produced invalid
values. If you get an internal error please contact me.

NOTE: 1019 is an error when trying to write to the resume file.  It almost
always means disk full (the resume file may need several megs).  This can
only happen in the first save of a session, the one that might need new
disk space.
You can also get internal errors if the resume file is in use by another
process when FZC tries to do a save/autosave.
Both problems will be corrected in future betas by reserving the space
before doing any cracking and keeping the file locked while FZC is running.
