JS script, Widget Warnings, Contact form

* JS script; improved lazy loading of external JS scripts; if the call
back method is not specified, system outputs an alert, but no longer
crashes the JS thread.
* Widget Warnings; changed output of warnings such that the warning no
longer tries to fill 100% height (which fails if the widget has padding)
* Contact form works again, displays warning when the button and/or
article link are not set