First attempt to split initTestboard function into parts accessible by their
own. We still need to make sure they are all executed at startup, which is
why they can only be run (actively) once the testboard has been initialized.

This still needs some love.
Minor change to textpxar.
Merge branch 'master' into split-init
Add new API helper functions to outsource checks on input configurations:
  checkTestboardPower() - checks for correct & sufficient voltages etc
  checKTestboardDelays() - does the usual register name lookup and checks
  verifyPatternGenerator() - existed before, but now also stores the PG in
                             the DUT object
API EXTENSION: new public API functions
  setTestboardDelays() allows to set new testboard signal delays whenever you want
  setTestboardPower() allows altering of voltages etc
  setPatternGenerator() allows you to update the PG whenever you like
All these functions require an initialized testboard, so calling
  initTestboard(...)
once is mandatory. This way we can make sure to have an initial valid set
for all parameters.
Provide facotrized testboard setting functions for delays and power
parameters. Call only these from the HAL initTestboard function. The
latter one is still required to make sure we have set up everything once.
API CHANGE: pxar::daqStart() does not accept a parameter anymore. New pattern
generator setups have to be provided via pxar::setPatternGenerator() and are
then stored in the DUT object.
Adapt tools to changed API function pxar::daqStart()
Adapt tests to new API function pxar::daqStart() without explicit PG.
use new API function setTestboardDelays(sig_delays) instead of
generit initTestboard().