Add box drawing glyphs

The "inco_syms" command draws the box drawing range.
Add "inco_scale" script

A collection of scripts for making smaller alphanumerics (fractions etc).
Add "inco_fix" script

This does a bunch of affine and lerp stuff to a specific version of
Inconsolata-vf.glyphs, to make suitable placeholders, and so that it's
possible to generate a 700 normal weight from the file.

It's hacky and there was some manual fixup required (mostly declining
the offer to automatically adjust glyph positions), but it's worth
having the logic in a repo, as it's likely that adapting it into a more
general tool in some form will be useful.
Add "merge" command

A simple command for merging in a layer from another font.

Also has some tweaks to make roundtrip more robust.
Add test font and script

I made a screencast, and these are the resources used during the demo.
The screencast is up at https://youtu.be/MUx9Rh-loqU
Add test font with rotations

Adds a test font that rotates the dot of /i and the tail of /n
Display filled glyph shape

Get structure from Glyphs font file, draw the interpolated glyph.
Start loading data from font

Loads a glyph from a font and populates a point cloud.
Import glyphstool

I'm moving glyphstool into this repo as a subdirectory, so that it can
be used as a lib, rather than maintaining it as a separate repo. This
commit has the lib structure but doesn't change any functionality.
Snap to latest druid version

Use delicious native radio buttons!
Add linear option

It's not bilinear though in higher dimensions, actually polyharmonic
with order 1.
Various refinements

Now a fake radio button choice for interpolation type (actually made
from checkbox). Progress towards better logic for editing point
positions at masters.

Also snap to latest druid (needed to get checkboxes).
Wire up lensing for masters

Clicking a master now sets the weight for the app.
Checkpoint while reworking the lens stuff
Add closure-based lens abstraction with pairing
Snap druid

Get latest druid (with style and layout fixes), tweak UI a bit.
Start getting masters into UI

Still WIP, the masters don't really do anything. At this point, more UI
work is needed to get things plumbed.
Add list widget

Update deps

Update to latest druid, and also bump rbf-interp version. We don't have
to special-case handling where the scatter is too sparse, because now
rbf-interp handles that correctly (using pseudo-inverse).
Very basic interpolation working

But there are lots of flaws. Biggest is that it's very hard to keep
points sparse, when you move the sliders it almost always wants to
add a new sample. Also, there may be numerical stability issues.