This patch allows to hide/show tree elemensts in the outliner based on their Type.
Idea behind this is not only having some more control over whats shown and what not, but also to gain performance in heavy scenes.
Quick tests here show that hiding object data alone can give a 10x performance boost :) [just having 2500 cubes and hiding the mesh datablocks]
Atm moment this is quite granular (see below), but the different options are grouped, so the user can quickly hide all "Object Data" e.g.
There is also an operator to quickly "Show All Types" again.
This will also enable a request like here:
here's how it looks: