#41 replaced the normal message dialog with the JXErrorPane, when clicking on a failed download
#42 check in DownloadManagerOptionsPanel if the newly choosen download directory is valid
#42 check if the download can be saved in the choosen download folder, if not abort the download
Merge branch 'feature/41-jxerrorpane-for-failed-downloads' into dev
Merge branch 'bug/42-download-to-directory-without-permissons' into dev