Reduce RSA key size

4096-bit keys are very costly.  Since they are only used for signing,
and not for encryption of data, they do not need to be future proof.
Add list of currently known security issues
Merge branch 'jake'
Improve basic integration test
Fix basic integration test process launching
Request next file when a file is received
Fix multiple file sync
Fix scanner test
Write to intermediate file
Add another test to integration test
Add other input for share mode
Remove rescan command
Enable change monitor
Fix change monitor
Further change monitor cleanup
Have connections subscribe to share changes
Scanner detects changed and *some* deleted files