Check for permission errors in queues and defer queue initialization until use. Fixes #1897.
Merge pull request #1899 from basilfx/mpfix

Multiprocessing IOError fixes
Oops, it should be an OSError instead of IOError
Merge pull request #1900 from basilfx/mpfix

OSError instead of IOError
Merge pull request #1901 from rembo10/develop

Develop