Add morphing

[MartinThoma]

It would be nice if the formula recognition would work continuous and morph the handwritten symbol in a typed one while writing.

e.g.

<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="6.752pt" height="10.904pt" viewBox="-1 -1 2 2">
  <path>
    <animate dur="5s" repeatCount="indefinite"
             attributeName="d"
         values="M 0,0
0.2567223442925333,0.0985613141741042
0.7566668192545555,0.644907513786763
0.8287222120496944,0.7657815372242689
0.8903889126247778,0.862238625919126
0.9416664971245555,0.9290621717437311
0.9726388719346666,0.9694655987394958
0.9952223036024443,0.9937075318408739
1,1
1,1
1,1
1,1
1,1
1,1
1,1;
             M 0.8032786885245902,0.2910284463894967
1,0.9277899343544858
1,0.973741794310722
0.860655737704918,1
0.7295081967213115,1
0.5901639344262295,1
0.45081967213114754,0.973741794310722
0.45081967213114754,0.9277899343544858
0.6557377049180327,0.29321663019693656
0.6557377049180327,0.2713347921225383
0.6639344262295082,0.2603938730853392
0.7295081967213115,0.2603938730853392
0.7786885245901639,0.2603938730853392
0.7950819672131147,0.26695842450765866
0.8032786885245902,0.2910284463894967;
             M 0,0
0.2567223442925333,0.0985613141741042
0.7566668192545555,0.644907513786763
0.8287222120496944,0.7657815372242689
0.8903889126247778,0.862238625919126
0.9416664971245555,0.9290621717437311
0.9726388719346666,0.9694655987394958
0.9952223036024443,0.9937075318408739
1,1
1,1
1,1
1,1
1,1
1,1
1,1;"/>
  </path>
</svg>

[MartinThoma]

This belongs to write-math: https://github.com/MartinThoma/write-math/issues/29