Renamed global to `HandlebarsIntl`

Closes #35
Merge pull request #36 from ericf/global-name

Renamed global to `HandlebarsIntl`
Cache {{inltMessage}} strings as IntlMessageFormat instances

This caches string messages passed to the `{{intlMessage}}` helper as `IntlMessageFormat` instances that can be reused with other templates or during re-renders.
Depend on new intl-format-cache helper package
Build