be DatalibExceptions. Log configuration file preferences overriding
database ones.

changes:

  * removed a bunch of functions that are either there for compatibility
    with many databases, or for moodle BC reasons.
  * Made most the functions throw exceptions instead of returning false on
    error
  * Code convention cleanup
  * Added lots of notes throughout the file on why changes were made

escaped or not, and made the default true. This allows some messages to
have HTML in them if required.

the session and retrieving them for display.

about a possible optimisation for the function that gets plugin config.

SQLException class.

suspect more functions in dml.php will need to be changed, but that was the
obvious one.

triggered by trigger_error.

added external library kses

performed.

and theme set up, parameter cleaning. This  is just being committed now
so I can pull, not to be considered complete

immediately after this file is included (this file now does not have any
dependencies). Remove the otherwise private log_message function from
backtraces.

two log targets, and the standard four log levels. Backtraces can be turned
on and off per log level also.