Check that map/hist functions are called with the right argument.

Check that map/hist functions are called with the right argument.

Change the parser to make clear() and zero() accept only local and
global variables as arguments.

Since the parser has no knowledge of the type of a variable abort
the execution if clear() or zero() are being called with something
other than a map or hist.

Fix assertions found by jasper@ with AFL++ (port coming soon!).

ok jasper@