Some ui reorganization of the physics tab:

* Before the different simulations all had a panel with an "add this" button making the whole tab look really messy. It also rarely makes sense to have more than one or two physics things enabled for a single object, so having all the panels in the tab just added a great deal of visual clutter.
* Now there is a single "enable physics for" panel at the top that allows for enable/disable of any simulation. All actual physics panels are hidden until a simulation is enabled.
* There was no "add" button for force fields before, but I added a toggle between "none" and "force" to unify the ui even further.

release/scripts/ui/properties_physics_fluid.py

@@ -29,7 +29,7 @@ class PhysicButtonsPanel():
     def poll(cls, context):
         ob = context.object
         rd = context.scene.render
-        return (ob and ob.type == 'MESH') and (not rd.use_game_engine)
+        return (ob and ob.type == 'MESH') and (not rd.use_game_engine) and (context.fluid)
 
 
 class PHYSICS_PT_fluid(PhysicButtonsPanel, bpy.types.Panel):
@@ -40,25 +40,9 @@ class PHYSICS_PT_fluid(PhysicButtonsPanel, bpy.types.Panel):
 
         md = context.fluid
 
-        split = layout.split()
-
         if md:
-            # remove modifier + settings
-            split.context_pointer_set("modifier", md)
-            split.operator("object.modifier_remove", text="Remove")
-
-            row = split.row(align=True)
-            row.prop(md, "show_render", text="")
-            row.prop(md, "show_viewport", text="")
-
             fluid = md.settings
-
-        else:
-            # add modifier
-            split.operator("object.modifier_add", text="Add").type = 'FLUID_SIMULATION'
-            split.label()
-
-        if md:
+            
             row = layout.row()
             if fluid is None:
                 row.label("built without fluids")