"help" text was used twice in two navigation menus: once in top navigation and
once in tab bar (along with "prrivacy policy" and "rules"). The "help" in tab
bar was changed to "general help" to avoid potential confusion.
- Most of model-related code moved from controllers to model classes, much
fewer calls to R::whatever() in controllers
- Post editing and uploading shares the same code, thus making implementing
stuff easier in the future
- Added support for default bean wiring, no more calls to R::preload() all over
the place
- More robust concurrent post editing detection
