Improve diff reports used for releases

[dosumis]

1. Diff should show before and after, not just after!
2. Add column for alignments - so we can track when additional alignments have been added for existing images.

[dosumis]

@admclachlan - could you have a go at improving the diff report?
Code is here:
https://github.com/VirtualFlyBrain/VFB_reporting/blob/master/src/reporting_tools.py#L84

I'll extend the Cypher query to track alignments.

[admclachlan]

Will do, I'll probably have questions when I get to it. Can you assign me to this issue? Github won't let me do it.