Delete favorite button

I extract drop-down menu actions to make them as button action in the page header.
I removed the favorite button on the category list because it is a duplicate from the button action.
Now button action act as filters and you can combine them.

It is a test to see if we can keep it like that. There is still work to do to extract other actions from the drop-down list.
I did not want to change everything if we don't keep it.

See #376 and #277
Change activate button layout
Fix DOM ids
Extract RSS feed from menu

The RSS action has now its own button. I also reorganized the button display order to be more natural.

I did not find an appropriate Unicode replacement for the Rss icon.
Add a new status for 'ALL'

I made the conversion in every file I can think of.
It should not have any reference to the string 'all' for the state context
Revert deletion of the favorite actions
Change rss icon fallback value
Move state constants from Configuration to Entry
Add active class on filter buttons
Add sort button
Add div.stick to collapse button space
Revert delete favorite button
Merge pull request #486 from aledeg/simple-layout

New toggle buttons to filter articles (was: Delete favorite button)