Fix btape bug with big blocksizes

there is an overflow when calculating the maximum file size, which leads
to a eof being written to the tape where btape does not expect it.

Then during the read of the data the unexpected eof lets the test fail.

This fix corrects this overflow.

We also set a higher debug level on the block writings in block.c

Fixes #381: btape tests fail on blocksizes > 256k
Add JobACL to monitor console to see jobs

Looks like before the status command did not limit the
view of jobs according to the JobACL.

As the ACLs now have been fixed, we need to allow the
monitor ressource to see all jobs because otherwise
we see nothing.

Fixes #378: Bareos tray monitor - not accurate information from
bareos-dir
Fix compiler warnings in btape
Cleanup device backend cache on exit.
Fix problem with getting symlink data on windows.
Fix director crash on dir command with long filenames

Fixes #383: dir command in bconsole crash bareos-dir