Fix Issue #53
Consolidate forms to facilitate maintenance, reduce code, and apply changes to SIP handling introduce for sccp
Delete form.addsdevice.php
Delete form.sbuttons.php
Delete sipconfigs class and move db functions to dbinterface class, and other function to helperfunctions
create new field type for SIP line
update 9951 buttons count in installer
simplify segregation of sip and sccp requests