Some badly encoded articles can be accepted as valid data.

Regression error since 0.7.9 (commit ccfbb07).
decoder.decode() no long ran into an excepton when no valid data was found.
Solved now by using the "found" flag.
Show warning when decoder encounters I/O-errors.
Plush: default refresh-rate now 4 sec and multi-ops bar visible.
Fix "Sorting" file renaming for RAR files that contain an extra folder level.

collapse_folder() should convert filename list accoerding to the renaming it does.
It's also its task to remove the _unpack_ markers from those filenames.
Rename this function to rename_and_collapse().
Fix regression error that could result in slow verification of NZBs with multiple rar/par sets.

The detection of obfuscated files failed, causing each par2 run to parse all files.
Update translations
Update text files for 0.7.11
Merge branch '0.7.x'