make sure "to" arg is an object, and has a url property before setting isFormRequest to true.
make sure "to" arg is an object, and has a url property before setting isFormRequest to true.

Fixes #377

hinaloe/jqm-demo-ja,hinaloe/jqm-demo-ja,npmcomponent/cbou-jquery-mobile,startxfr/jquery-mobile,startxfr/jquery-mobile,hinaloe/jqm-demo-ja,arschmitz/uglymongrel-jquery-mobile,arschmitz/jquery-mobile,startxfr/jquery-mobile,npmcomponent/cbou-jquery-mobile,arschmitz/jquery-mobile,arschmitz/jquery-mobile,npmcomponent/cbou-jquery-mobile,arschmitz/uglymongrel-jquery-mobile,rwaldron/jquery-mobile,rwaldron/jquery-mobile,arschmitz/uglymongrel-jquery-mobile