Ft.autohiding headerbar
Rework of the headerbar and bottombar
This PR:
-
Makes the textview to go all the way to the top and the bottom of the window, even behind the headerbar, so when it disappears any visible gap is left
-
Makes the headerbar and bottombar to disappear instantly when writing, and they reappear when moving the cursor to the top/bottom areas. If the cursor moves to the bottom area only the bottombar is shown, when moving the cursor to the top area both headerbar and bottombars are shown