Change argument names in ticables.pxd

Change function argument names from "handle" to "calc_handle" for all
CalcHandles.
Better memory handling in receive_bytes

Add NULL checking and a call to memset for the buffer in receive_bytes.
Clean up ticables.pxd

Remove unused definitions in ticables.pxd and make function argument
names more consistent. Any definitions needed later can be added back
in.