PalmOS support

[Brian Hook]

Ryan and I have been talking a bit about the ability to support 
PalmOS.  PalmOs is a notably ugly operating system to program for 
because of its limited resources -- it uses mem handles that need to 
be locked, etc.

I'm not a PalmOS developer, but I've read some documentation, and I 
think that it would be reasonably easy to add basic support to it 
modulo standard portability weirdness.

The key issue is whether to try to handle loading binary resources 
within PhysFS or have the application be responsible.  I'm leaning 
towards the latter, and I've been thinking that this could easily, 
almost trivially, be accomplished by adding a new entry point like:

PHYSFS_addBitsToSearchPath( const char *name, 
                            const void *data,
                            int data_dize,
                            int format );

It would then work normally, but when searching for a file there would 
be a preloaded image in addition to disk images that it could search.

This way the app is responsible for loading, allocating and locking 
the data resource, but can otherwise rely on PHYSFS to handle archive 
read/write.

The major downside to this is that you have a locked chunk of memory 
at all times, which may not be feasible.  I'm not sure if a clean API 
for handling lockable resources would be worth the trouble though.

Brian