[nobruinfo]

The by #52 suggested defrag command I have no idea how to implement.
So this PR consists of the following:

• Instead of altering the existing dir a direx command was added. It adds an extra column (or columns to come) but is not used by M65Connect™ currently, hence not breaking compatibilty. In the extra column the fragmentation status is shown taken from the function discussed in the issue ticket. I have this active in my test fork for months and it's showing a fragmented file from time to time. There's also known ways to del files leaving them as corrupted. This PR does not yet fix this.
• Similar to the recently established df command a fraginfo command to recursively visit all directories of the storage to only list fragmented files. It came out not to be as slow but people can still [Ctrl][Break] out of mega65_ftp entirely to stop this.
  To make gtest work the change from PR 244 was added also here. Also it was adapted to test added things in dir and df correctly.