cache uidvalidity
remove size calculation until we defer it to thread properly
defer fetch-all-flags too
avoid unneeded db index updates and rdoc creation
catch soledad error while updating mbox doc
fix attribute error on debug line
fix rdoc duplication
catch stopiteration
catch empty rdoc
ignore keyerror on deletion
Merge remote-tracking branch 'refs/remotes/kali/feature/speedup-select' into develop