Checks if CUSTOM folder was successfully created. If not, prints qDebug message and proceeds as normal except uses default card images instead of custom ones.

Ref #127

It's always windows.

If the sounds path is unset in the settings and a “sounds” directory
doesn’t exists in the user’s data directory, install the sounds files
and set the settings value accordingly

 If none of the gameboard images is set and and the user’s data
directory doesn’t contain a “zonebg” directory, create the directory,
copy contents from cockatrice’s app bundle and sets the config
accordingly.

If the sounds path is unset in the settings and a “sounds” directory
doesn’t exists in the user’s data directory, install the sounds files
and set the settings value accordingly

 If none of the gameboard images is set and and the user’s data
directory doesn’t contain a “zonebg” directory, create the directory,
copy contents from cockatrice’s app bundle and sets the config
accordingly.

Better error message and allow the user to still connect

Ref: #102

Use QDesktopServices::StandardLocation for platform independent default paths that don't touch the application's own folder