documenting. Removed some done todos, and added a few more, mostly to do
with finishing off the documentation.

be removed.

debugging lines as the function has changed name.

hopefully to be a bit more readable. Only call session_start() in the
create_session method if the session is not started, I am noticing some
occasions where it appears that a session has started by $_SESSION is
empty.

  * Re-organised the file a bit, to better logically group some stuff
  * Renamed the log_dbg function to log_debug
  * Added a third parameter to the logging functions to say whether a
    backtrace is required.
  * Fixed up projectname in default exception handler.

  * Removed three methods that are unused
  * Changed log_dbg calls to log_debug, which is what the function is now
    called
  * Removed language section reference that only adds bloat now there is a
    default
  * Removed a couple of done TODOs
  * Added a function that allows each authentication method to validate
    their own configuration form.

submitted file value correctly for file fields. Moved the hsc function to
lib/mahara.php

element types.

* get_rows()
* get_rows_select()
* get_rows_sql()