Storage of session in database works with cs_authUser

NOTE:: some optimization and cleanup is still necessary.

Summary of changes:
 * minor changes to facilitate debugging
 * check_sid() uses parent::is_authenticated()
 * login() fixed to properly integrate with cs_sessionDB
 * $_SESSION['uid'] now used
 * logout_sid() works
 * logout_inactive_sessions() calls sessdb_gc()
 * set timezone arbitrarily (for now) to avoid warnings //CLEANUP!
 * logs of file-based debugging //CLEANUP!
 * fix sessdb_read() to work properly with cs_phpDB PDO changes
 * fixed doInsert()
 * fixed doUpdate()
 * fixed updateUid()
 * fixed sessdb_write() // CLEANUP!
 * fixed sessdb_destroy()
 * fixed sessdb_gc()
 * use exception handling in do_log()
 * exception handling in exception_handler()...
 * file-based logger method, "flogger()"
 * method for is_authenticated, for compatibility with contentSystem{}
 * methods for creating parameter-based update/insert SQL strings
Cleanup + comments
Cleanup