by douggreen: re-added missing callback property to the validate function. Might actually not be necessary...we'll see.

by douggreen: Removed additional t() calls; added str_replace() to exporter to match coding standards.

Save routines should now pretty much be functional. The problems appear to now pretty much be limited to context loading/generation at render time. It's not clear if the problem is with panels_page logic, the Panels engine, or some squirrely D6 changes.

Changed name of argument error code constants slightly; added brackets in panels_load_include() for clarity.

Fixed an old error code constant; relocated the handlers to higher up in the file; moved sanitizer back into this main file, other odds and ends.

Updated function signatures to include $subtype as first parameter; also cleaned up repetitive copy/pasted docblocks on many render callbacks.

Docblock updates and changes in code style for references to match merlin's ($a = &$b instead of $a =& $b)

Panels page have any of its own ajax - it's all done by the panels engine. This file was superfluous.

Rewrote master loader to accommodate static panel_pages; rewrote admin loaders to accomodate changes in menu arg processing; moved several more functions out into their respective inc files; added a bunch more docblocks.

Updated panels_page_load() to make use of a fetcher when called on an already-cached $panel_page that doesn't have the primary display loaded, although that use case is deprecated and should be avoided (for the sake of clarity). Other than that, mostly minor touch-ups.

Incremental commit - added a few missing inc loaders; also added the import page form. Next - fixing all the submit functions! yay...

'Write' functions - functions that are concerned with putting data in the database, or some other form of storage. The latter is the conceptual justification for putting export functions in here, too...which was originally done for practical reasons :)

Init import; all functions dealing with retrieval & rearrangement of panels_page-related data is contained here.

The panels_page_fetch*() family of functions were also notably refactored from when they last appeared in the panels_page.module file; they are now much more targeted, single-purpose entities with clear inputs and outputs. See the docblock additions for details.