Prefer attach-point to data-attach-point.
Fixes #210.
Support requires="..." attribute in templates to load specified AMD modules.
This means that delite/handlebars! used as a plugin can compile any template,
even if it contains widgets.

Inadvertently fixes #159 because users will never use text! to load templates anymore.
fixes #189 (unreported failures)
bump version to 0.1.7