Now DAQmx write commands are handled ok

Turns out the errors that were being thrown were due to trying to use a
pointer to a memory location and failing in daqanalogwrite command. I
just replaced that call in the function to a NULL pointer and all is
grand.
Hall probe daq read works, yoko gpib fleshed out

Compiles and runs successfully. can read and output data successfully on
DAQ. Yoko and agilent GPIB finished but untested.