Make DAQ I/O ports etc. configurable

[marktsuchida]

Currently hard-coded:

• /port0/line5:7 for clock outputs (should be user-configurable; also clean up redundant outputs and make polarity configurable)
• /ctr0 for line counter (ok)
• /PFI12 assumed to be output of ctr0 (and used as start trigger for analog-input task) (see below)
• /ao0:1 for scan waveform output (should be user-configurable)
• all analog inputs returned by DAQmxGetDevAIPhysicalChans are assumed detector inputs (ok)

For PFI12, can we use Ctr0InternalOutput instead?