Create some default styling for the input widgets provided by "date".

First off, thanks for the patch. But there are a few things that I'm not sure of about this one. This is overriding classes like "date-no-float" from the date module... maybe this should be applied to the date module itself? Or figure out why there are no-float classes before we override them? Also, this only applies to the default date field type - do we want it to apply to the Unix timestamp and the ISO format? Also if the "Show end date" checkbox is enabled, it doesn't look so nice.

I'm not against this, just want to make sure it's not going to mess something else up, and we keep it consistent.