the callBack class becomes obsolete with these but all places where it is used are updates

fixes https://bugs.kde.org/show_bug.cgi?id=259616

Seems we don't really need this, since calling e.g. fileActions['audio/x-wav'] is no problem. It should be also more clear to use and read than e.g. fileActions.audioxwav

replaced fileActions[this.mime] by fileActions[this.mime1 + this.mime2], since an object name cannot contain slashes. (correct me if I'm wrong)

Patch by Romain GRENIER

bug fix when starting multiply uploads while the old ones arent finsihed, detect file actions on mimetype not on extention