Dynamic engine options in UI for blender / ffmpeg (#66)

* Make sure progress UI updates occur on main thread

* Cleanup unnecessary code in FFMPEG

* Cleanup extension matching

* Make sure supported_extensions is now called as a method everywhere

* Fix add_job crashing

* Update the renderer to reflect the current file type

* Sort engine versions from newest to oldest

* Consolidate Project Group and Server Group

* Split UI options into its own file for easier updating

* Add ffmpeg ui stem

src/engines/blender/blender_ui.py

@@ -0,0 +1,8 @@
+
+class BlenderUI:
+    @staticmethod
+    def get_options(instance):
+        options = [
+            {'name': 'engine', 'options': instance.supported_render_engines()},
+        ]
+        return options