lest breaking current API, though, it is noted in the documentation of TabContainer
class, of the upcoming Godot (v3.0+) changes in behavior, that is, `tab_selected` will be
emitted for selecting any tab, while `tab_changed` only if a tab changes.
- Added `get_previous_tab()`. Which returns the previous shown tab. **Note:** In Godot v3.0+, only `tab_changed` can modify previous tab index.
- Add documentation for the added function and signals. Fix a typo too.
That year should bring the long-awaited OpenGL ES 3.0 compatible renderer
with state-of-the-art rendering techniques tuned to work as low as middle
end handheld devices - without compromising with the possibilities given
for higher end desktop games of course. Great times ahead for the Godot
community and the gamers that will play our games!
(cherry picked from commit c7bc44d5ad)
