Hide "unfinished" blocks from the toolbox for EOY prototype

[tmickel]

This is my accounting:

• say
• say for n secs
• think
• think for n secs
• entire pen category
• show variable/list, hide variable/list.
• when "loudness"/"video motion" > _ (timer works).
• ask and wait
• answer (for ask and wait)
• loudness
• video motion reporter
• turn video on/off
• username
• "more blocks" category

[tmickel]

Other notes:

• All motion blocks do not match Scratch 2.0, because they don't keep in fence/stage. I'm assuming we need motion blocks for the EOY prototype, so this can either be on the list or we could be fine with the non-matching version.
• "change size" and "set size" do not match Scratch 2.0, because they don't limit size relative to the costume size.

[TheBrokenRail]

Maybe iterating through the blocks and checking if they are implemented (if they have a primitive) and hiding the ones that don't.