Add 'checkDisabled' and 'checkAttrName' settings

[jordisan]

Add a setting to make it possible enable/disable disabled fields checking. Useful since 'propertychange' event is not supported by most browsers, so if you change the "disabled" attribute programmatically, the plugin doesn't work properly

Add a setting to make it possible enable/disable checking whether field has 'name' or not. Useful if you are using AJAX, in which case you might have fields without "name" that you want to track

[codedance]

checkDisabled sounds reasonable and is in effect self documenting.

I think checkAttrName could be more appropriately named and/or document. Maybe checkUnnamed?

History: Unnamed fields are not sent on form submits and hence are ignored. It does however make sense for the AJAX case you've put forward so it's a reasonable change.

I'll merge once we've decided on the most appropriate name. Getting the external API/names are important as they are hard to retrospectively change!