improve logo escaping (badges#3511)

* escape logo in make-badge

* 2.2.1 release notes

* tighten up validation of logo param

gh-badges v2.2.0 (badges#3501)

cut a v2.1.0 release (badges#2354)

bump version (badges#2296)

Give the NPM package some love (badges#2200)

* define a public interface for NPM package
* move check-node-version to dependencies
* add missing file to package
* update docs
* bump version
* add gh-badges option to issue template
* abstract text measuring from users
* add a DocBlock for BadgeFactory.create()

Allow specifying a custom font path in the library