fix some pep8 problems for metadata community
add metadata check and delete
add delete metadata
add check thumbnails using PIL
merge skinratio() and some other fixes
limit metadata thumbs to be at most 512KB
limit the number and size of the automatically created thumbnails
fix
small changes
some changes
Merge pull request #863 from LipuFei/enhance_metadata

Check metadata thumbnails
Fix selectedFiles when coming from commandline
Added missing dependency to README.md
Fix on_tracker_warning_alert
Merge pull request #868 from egbertbouman/small_fixes

Fix on_tracker_warning_alert
Silence wx image errors
Merge pull request #867 from egbertbouman/cmdline_fix

Fix selectedFiles when coming from commandline