Don't instantiate a TextureStore each time we pick something in the scene

[oktomus]

We recently added printable settings on texture store (8d949848e376a8e93fb516dcaabdb7f7dfe88b2b). These settings are printed when the store is created. Thanks to this, we noticed a bug in appleseed.studio: each time the user wants to pick a material or an object, a new TextureStore is created.

The reason is that a ScenePicker is instantiated each time we call pick().

Because the picker is project based, we could just create it once.

Make sure to test in debug, and make sure to test picking during and after rendering, and after loading another project.

[iamarchisha]

So, this should not be printed everytime an object is picked or selected?

[oktomus]

@archisha-chandel The store settings block should not

[achalpandeyy]

Hi! Is anybody looking into this? I'd like to take a stab at it.