testing clipboard functions

This test only needs an empty DragonPad window.

Also testing some of the meta actions like

• <<select all>>,
• <<copy>> and
• <<paste>>.

Especially the USCs

• CLIPSAVE and
• CLIPRESTORE are tested here, with the intermediate
• CLIPISNOTEMPTY, which returns false if the clipboard is empty.

Call with Unimacro test clipboard.