Moved dictionaries and settings to SM prefs system

Moved dictionaries and settings to SM prefs system
Fixed use of $SCRIPT_NAME globals
Removed SQSPELL_EREG setting. Internal dictionary format was changed, use
of ereg is unstable due to mbstring.fu*** :). It would be better to use
boolean configuration option.
Fixed use of php 4.1+ POST and GET vars
Fixed some script errors that might appear when SQSPELL_APP is changed or
invalid module name used in URL.

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@9403 7612ce4b-ef26-0410-bec9-ea0150e637f0