DEzs error message with missing boundaries about bayesiantools

[stefan-paul]

The problem is that the sampler does not know the number of parameters in the setup if
no boundaries are provided.
bayesianSetup$numPars is 0.

[florianhartig]

then the trick would be to see if a sampler is provided, and if so, create a sample to check. I think this is used in other places of the setup.

[florianhartig]

Two more things

a) is numPars essential? Should we throw an error if it can't be derived?

b) Even if it is not essential, we should probably notify the user that there is an issue - if it's not essential, better a message than a warning, but some notification would be good, because from the error later an average user will have no idea what the problem was.

[stefan-paul]

Wait.. I fixed this. There was already a line to catch possible errors but it missed
the case if the sampler is provided in the prior.
I'll push it with the other things.

[stefan-paul]

Done 06e2344 .