Make RotationCenter to be half of cam-ROI if nothing found in log.

If you do not run sinooff_tomcat_j.py prior to the PaganinIterator, you do not have information on the RotCenter in the logfile.
In this case just set half of the camera window width to be the rotation center and let the user decide if that's good or not.
Adding script to watch space on disks and basic exclude.txt

'watchspace.sh' just calls 'du' for all 'disk' subfolders in Data10, so the users can see how much data will end up on their disks.
'exclude.txt' is a basic exclude file handy for the rsync-call, as seen here: https://intranet.psi.ch/Tomcat/BeamlineManual#Data_transfer_for_users_44_data_backup_for_you
Merge branch 'master' of https://bitbucket.org/psitomcat/beamline-scripts
Correcting typo
watchspace renamed to watch_Data10

Additionally only running the command every 20 minutes or so, since - according to Heiner - it's nearly bringing the fileserver down if run every few minutes...
Adding snippet to watch filling of external disks
Reliably delete the leftover reconstruction

When switching to another slice, the old reconstructions were not
deleted from the 'sin' directory.
We are thus deleting all '*rec*' files, which takes care of everything.
Also only reference the LogFileLocation once we know it (this bug only
showed up if you used the 'verbose' option).
Merge branch 'master' of https://bitbucket.org/psitomcat/beamline-scripts