Safesql

:bangbang: not ready to merge. Just using it to track changes.

* [x] Category
* [x] Comment
* [x] CurrentUser
* [x] FrontPage
* [x] Image
* [x] Media
* [x] MediaPhoto
* [x] MediaPhotoImage
* [x] MediaVideo
* [x] Page
* [x] User

Fixes #64