pdProfiler: minor clean-up
pdPackager: start working on relevant chunk flags

The new setBitFlag and getBitFlag functions should make reading and
writing bit flags extraordinarily simple, even from within the confines
of VB6.  (I will never forgive them for not providing unsigned data
types, argh!)

The first implemented flag is automatically set by the packager on a
per-chunk and per-node basis.  PDP_FLAG_ZLIB_REQUIRED indicates whether
a given chunk (or node) requires zLib in order to be read.  It is
automatically set if a chunk's (or node's) contents are compressed at
creation time.

If a user wants to know if a given PDI file requires zLib for reading,
they can use the new getPackageFlag function, specifying
PDP_FLAG_ZLIB_REQUIRED as the flag, and PDP_LOCATION_ANY as the location
(to see if any chunk in the file has been zLib-compressed).

This behavior was a prerequisite to implementing second-pass directory
and data chunk compression.
PDI loader: if a load operation fails, and zLib is not enabled, report a specific solution

This was basically a test case for the new PDI flag code, which seems to
be working well (phew).

To ensure backward compatibility for existing PDI files (of which I am
probably the only person in the world to have any, ha), file compression
state is not checked in advance.  PD will blindly try to load PDI files
regardless of contents, and if a failure state is reached, it will then
check for zLib incompatibility.  This approach should ensure that old
PDI files created from nightly builds play nicely with the new flag
system.