Cannot check this against NULL. refs #10081
Added accessor method to get member variable.

Added PoldiInstrumentAdapter::getChopperSpeedPropertyName()
refs #10081
Modified buildscript for clang

If the jobname (only on mac for now) contains clang then
we will use clang rather than intel for the compiler

refs #10081
Merge remote-tracking branch 'origin/feature/10081_clang_compilation_mac'