Add 'fixpyramids' command to admin.py

'bin/omero admin fixpyramids' will now remove any 0-length pyramid files
that do not have a corresponding lock file or temp file.  This allows
administrators to force regeneration of pyramid files that could not be
created before (e.g. due to OOMs as a result of the server
configuration).

See ticket #11395.
Refactor fixpyramids to act more like cleanse
Refactor to use os.walk
Lower ERROR to WARN on purged log
Fix FullTextIndexer header
Fix FullTextIndexer whitespace
Lower 'Unknown action type' to DEBUG
Add heap-dump{-tmp} blocks to Java servers in templates.xml
Remove $revision.
Add tests to move images with rnd settings.
Add more tests.
clean up.
Remove unused import.
Load the metadata for wellsample.
Initial tests to delete projected image.
Replace move by delete.
Clean up code and remove duplicate tests.
Remove $revision.
Make sure the correct use delete the image.
Simplify test.