This updates my two Video4Linux-2 drivers for the "Hexium Gemini" and
"Hexium Orion" cards.

It adds the long missing input handling for the "Gemini" card and
removes the annoying compile time warning about unused structures.

 - remove various hexium header files, put all driver relevant
   informations into the drivers.  these informations are not needed
   anywhere else. 
 - fix driver names in information printk()s
 - fix device initialization for Hexium Gemini cards
 - add input switching for Hexium Gemini cards
 - fix all remaining "fixme"s