Torrent Queuing for Botched torrent (#83)

* Implement a queue for handling failed torrent

* Add checks for getting slots

* Few other cleanups, change some function names

pkg/webdav/file.go

@@ -86,7 +86,7 @@ func (f *File) getDownloadByteRange() (*[2]int64, error) {
 
 func (f *File) stream() (*http.Response, error) {
 	client := sharedClient
-	_log := f.cache.GetLogger()
+	_log := f.cache.Logger()
 
 	downloadLink, err := f.getDownloadLink()
 	if err != nil {