Select mesh when focusing camera on mesh

[Zishan-Rahman]

No description provided.

[tracygardner]

@Zishan-Rahman I took a look at this and there are a few problems:

• The F key should only work when on the workspace so it doesn't interfere with keypresses on the canvas (we can also add a button)
• showBoundingBox sets the visibility of focussed shapes to 0.001 making them disappear.
• When I focus a second mesh (by clicking on a block and pressing F) the focus stays on the first mesh. It looks like window.currentBlock isn't updated.

[Zishan-Rahman]

The first mesh needs to be deselected before focusing on the second mesh. Somehow we need to do that "unfocusing" from the code editor, rather than the canvas (where that's already possible).