Clean exceptions

[joefresna]

Exceptions, such as warnings and errors, are sometimes raised with a print("Warning message"). They should instead be raised with raise exceptions.MuMoTWarning("Warning message")

[joefresna]

Created branch for this, named clean-exceptions.
The commit f1d090b of that branch cleaned the part of stochastic analysis.
Other views and models have still some print()

[jarmarshall]

(quoted from #318)

I changed my old print("Warning message") with
raise exceptions.MuMoTWarning("Warning message") (as indicated in #352), however this stops the program. Instead, the desired behaviour is to let it keep running and just print the warning message. How shall I do that? Do you know, @jarmarshall ?

I think you can use warn() from the warnings module...

[jarmarshall]

PS some warnings should go to the log, some should probably be displayed. Most probably should go to the log - so need to pay attention to this...