Support equation environment - Bump to 0.7.1 (#23)

* working equations

* added equation tests

* fix newlines in equation env.

* update changelog

* update cargo version

* fmt; fix broken tests

add version to changelog

fix changelog

fix semantics

update cargo.toml version

update changelog (#14)

fix ci

fix ci once again

changelog for 0.5.0

zip artifact for font files

set version to 0.3.0