Add Block elements from the Symbols for Legacy Computing

[joshka]

1FB70 to 1FB8B inclusive (28 glyphs of 212 total in the block)

This is my first font editing experience, so I'm sure I've probably messed something up. In particular, I think at least one of the glyphs I duplicated and edited the original rather than the duplicate. I think this explains the removals in the diff

Issues I ran into (notes for others following a similar path):

• The latest version of glyphs mini is later than the current glyph file, so any edit make a bunch of extra edits to the file. You can find the download that matches by checking homebrew history. Homebrew/homebrew-cask@c18f1f5 -> https://updates.glyphsapp.com/Glyphs3.0.4-3108.zip
• Don't accidentally open the TTF in glyphs mini when trying install it, and then do a bunch of work on all the glyphs and then close the ttf and lose it all. That really blows :D
• ran into intermitten problems running the docker image. Usually running git clean -f got me past the problem though.
• That glyphs file format would be much easier to visually diff if it had indentation

[joshka]

Reading a little more, I think I might have messed up the production names changing them to uni12345 instead of u12345 at least according to https://glyphsapp.com/learn/getting-your-glyph-names-right

[tonsky]

Thanks! Merged

I agree working with .glyphs format is a pain :( Not git-friendly at all

[joshka]

Thanks! Merged

Closing out as merged in the related commit.