updated pointer and parameter structure

Per recommendations from...

http://stackoverflow.com/questions/14418388/pulling-return-parameters-using-ctypes/14418895#14418895

Also restructured the type dictionary to minimize text (ie using
assignment instead of a dictionary).

Included error function (and incorporated it into VCS_OpenDevice), so
that intelligible error messages can be displayed.

Should be at a good place to test motor control