Add multiple properties comparison page.

- Add route for getting all properties.
- Store entity_id in history as part of sensor id.
- Display "fetching data" information when loading data.
- Add navigation.
Filter properties by user's permissions.
Move log function into common
Don't parse profiles and images in index-all.

- Tidy up the logging
Merge pull request #119 from MastodonC/feature/multi-property-comparisons

Feature/multi property comparisons
Session and security with prepared statements.

And always getting things by primary key.