You can put values for a property in the query string of a new
object definition.

E.G. https://issues.roundup-tracker.org/issue?
@template=item&type=behavior

However if the type property had a default_value defined in the schema,
the value specified in the url is ignored.

If there is a value in the URL, it should be used. If the value
is unset after looking at all sources for the value, then use
the default_value.

Also if an invalid value is supplied in the URL for a property
without a default_value, we get a traceback. If the URL value is
invalid, it should just be ignored.

Fixed in changeset: 6404:e29d5f4e0af4.

Pushed use of default_value down the stack after the check for matching 
property in the form is done.

Added two new tests in addition to making an existing test
work and actually assert something.