v0.1.0 of stroke_morph

Universal morphing for stroke-based icons with spring physics — any icon morphs into any other, with rotations that emerge from the math. Changelog excerpt: First release. An unofficial Dart/Flutter port of [morphicons](https://github.com/guillermolg00/morphicons)by Guillermo. - Any stroke icon morphs into any other. Rotations, scalings and folds are not authored — they fall out of a closed-form Procrustes alignment between the two point clouds. - `MorphIcon`with three modes: uncontrolled (`icon`), controlled (`from`/`to`/`progress`), and imperative (via `GlobalKey`). - `MorphController`for driving a morph yourself, with `morphTo`/ [...]