Show document error

[zanbaldwin]

The show_doc() and show_error() are meant to intertwined with one another, though they really have not been thought through properly.
Error reporting is an extremely important aspect of the framework, so this must be rethought, and rewritten.

[zanbaldwin]

show_doc() has now been merged into the show_error() document.
show_error()'s parameters have been juggled around too, so any instance of show_error() has been altered to compensate for that. Parameters are now $header (which defaults to 500 Framework Application Error) and $message.