Add comment on forcing setIgnoreError to true

The testFailIgnore is the only parameter that is not passed to the
underlying soapui runner, because failure detection is delegated to the
mojo (mainly to make the test goal work with the test-verify goal).
So this difference diserves a short explanation
Remove extra null check in the Abstract mojo #118
Prevent NPE when setting endpoint #118

SmartBear implementation trim the parameter passed to the setter. So in
our OSS and PRO custom Test runner, we perform the null check prior to
call the setter.