Monster Bash: Complain when trying to enlarge files beyond 64K

The file format stores compressed and decompressed sizes in UINT16LE fields,
which means the largest file that can be stored is 65,536 bytes, both before
and after decompression.

This fixes the error where the .DAT file would unexpectedly become corrupted
after saving maps.
Make hexdump in test output easier to read
Allow resizes to fail without corrupting the archive

This changes the order of some operations so a failed resize (e.g. because the
new size is too big for the archive format) won't corrupt the archive.

A new test is added to attempt a resize > 64K which fails (now gracefully) with
Monster Bash .DAT files.
Update autoconf files listed in .gitignore