Needed cleanups/refactoring

• Rethinking 'what' header files are included 'where'. At the moment there are a hugh number of headers included in most .c (and some .h) files, some of which probably don't need to be there. Some possible solution is to create subsystem .h files that aggragate all of the other headers in that subsystem. With the goal of reducing the total number of headfiles that need to be include and thus, hopefully, making it more obvious which includes are need (and which ones can be removed).

• psAlloc()/psRealloc() will currently allocate a memBlock with a usermemorysize of 0. This probably should be disallowed but at least psArrayAlloc() is depending on this 'feature'.

• Change psArrayAlloc() to either set .data to NULL or to allocate an array of some reasonable number of elements (say 10?). The currently behavior of allocating an array of zero bytes is wasteful.

• be consistent about FILE, etc. being passed in on the RHS or LHS of the argument list. LHS probably makes more sense as RHS passing could interfer with varargs.

• Change the most frequestly used allocators, e.g. psMetadataAlloc(), psListAlloc(), psArrayAlloc(), to accept FILE and to pass this information on to p_psAlloc().

• completely dump all of the existing XML work. This feature should be respun to resemble the psMetadataConfigFormat() API.