New test for download with already existing file

...ain/java/de/uniwue/swp/dragdropssh/ssh/SSHManagement.java

...ue/swp/dragdropssh/ssh/tasks/console/CreateDirectory.java

...a/de/uniwue/swp/dragdropssh/ssh/tasks/console/Delete.java

...ragdropssh/ssh/tasks/console/WorkingDirectoryHandler.java

...iwue/swp/dragdropssh/ssh/tasks/transfer/DataTransfer.java

...p/dragdropssh/ssh/tasks/transfer/DataTransferHandler.java

...e/uniwue/swp/dragdropssh/ssh/tasks/transfer/Download.java

...gdropssh/ssh/tasks/transfer/TransferDirectoryHandler.java

.../de/uniwue/swp/dragdropssh/ssh/tasks/transfer/Upload.java

.../uniwue/swp/dragdropssh/ssh/tasks/console/DeleteTest.java

.../swp/dragdropssh/ssh/tasks/console/ListStructureTest.java

.../swp/dragdropssh/ssh/tasks/console/MakeDirectoryTest.java

...iwue/swp/dragdropssh/ssh/tasks/transfer/DownloadTest.java

...uniwue/swp/dragdropssh/ssh/tasks/transfer/UploadTest.java

...e/uniwue/swp/dragdropssh/ssh/tests/ListStructureTest.java