add appveyor configuration

[vlovo]

intial commit of appveyor configuration

[coin-au-carre]

Seems like there is a wrong path ? https://ci.appveyor.com/project/coin-au-carre/slacking

Btw for the contributor section maybe your email provided is not the one associated with github ?
See https://code.bradymower.com/why-arent-my-commits-showing-up-on-my-contributions-graph-52141efa7542

[vlovo]

Thanks, I fixed the email adress in my TortoiseGit configuration. Effectively there was a typo......

cmake --build . --target check

has to be replace by
cmake --build .

(there is no target check ...)

[coin-au-carre]

Ok nice feel free to commit this change so we cant test the new email :)