Added new 'setnulls' option for SQL model update function. If set to true this will force the setting to field values with a 'null' value to null rather than ignoring them.
Added new 'setnulls' option for SQL model update function. If set to true this will force the setting to field values with a 'null' value to null rather than ignoring them.

git-svn-id: cc6bf778016782145e08f50c22fd3532de014314@537 eaaf3d48-7251-11de-8585-3f51e31374b7

darkredz/DooPHP,darkredz/DooPHP