"show unread entries" button now looks like a regular navbar button.
"Mark all entries as read" button now looks like a regular navbar link.
Removed SASS file with CSS rules related to navbar buttons.

The app no longer uses navbar buttons, but rather regular navbar links.
Display de Add Subscription button as a regular navbar link. Group several navbar buttons under a single dropdown.
Reordering of options in the entries management dropdown menu.

Fix acceptance tests to account for the grouping of several buttons under a single entries management menu.