Update LinkPreview plugin for multiple notice forms.

Update LinkPreview plugin for multiple notice forms.

* main notice form setup now encapsulated into SN.Init.NoticeForm(form) -- this can be monkeypatched by plugins to append their own setup code, as LinkPreview does
* LinkPreview now supports debugging with non-minified JS source when $config['site']['minify'] is false
* tweaked core & neo styles so 'notice-status' class gets same styles as attach-status, so we can more easily add mroe statusy things. (needs more consolidation with geo-status, etc)
* tweaked LinkPreview's preview area to use that style