Add route to latest screenshot for use in automation

[vollstock]

It would be great to have a direct routes to screenshots (and thumbnails).

This way we can display the current status in an automation system without checking the latest date from JSON via the REST Api.

Latest

GET /tooloop/api/v1.0/screenshot/latest

http://<IP>//screenshots/latest
http://<IP>//screenshots/latest?size=thumbnail

Index

GET /tooloop/api/v1.0/screenshot/<int:index>

http://<IP>//screenshots/<int:index>
http://<IP>//screenshots/<int:index>?size=thumbnail

Date

GET /tooloop/api/v1.0/screenshot/date/<string:date>

http://<IP>//screenshots/date/<string:date>
http://<IP>//screenshots/date/<string:date>?size=thumbnail