Better feedback when accidentally inputting ID 0 into a new ORM object

[joepie91]

When reusing a value from elsewhere by inputting it into the constructor for a CPHPDatabaseRecordClass-derived object, and that value happens to be 0, any sufficient calls to properties will result in a cryptic "check your schema" error.

Example problematic code:

$value = 0; /* pretend this came from an external source */

$sSomething = new Something($value);
echo($sSomething->sSomeProperty); /* throws schema error */

Fix: if an object is marked as 'new' (that is, not originating from the database and created with a source value of either 0 or nothing), throw a more specific exception when the code attempts to access a property, indicating that no data has been loaded into the object yet.