Version 1.0.2.0 was not packaged correctly.

* Do not make uppercase greek letter italic #71
* Convert dash (U+2D) to minus sign (U+2212) #70
* Improve the custom la-tex element demo (renamed and updated to custom elements/shadow dom v1, use MutationObserver etc).
* Add example "Gamma with integral, large operator and square root"

- internal refactoring to generate a temporary abstract tree structure instead of a string https://github.com/fred-wang/TeXZilla/issues/10
- avoid extra mstyle attribute when setting mathvariant/mathcolor/mathbackground attributes on token elements https://github.com/fred-wang/TeXZilla/issues/61
- avoid using mathvariant attribute on token elements when direct transformed characters can be used https://github.com/fred-wang/TeXZilla/issues/62

- Migrate to WebExtensions format.
- Regenerate icons.
- Use minified TeXZilla-min.js to speed up loading.