Blueprint should support same features set as standard chalice routes

[philippeauriach]

The generate_default_docs=True settings was already supported on ChaliceWithSpec, but was not taken into account when using a blueprint.

This PR fixes that, setting generate_default_docs=True on the main ChaliceWithSpec instance will generate docs automatically for blueprints.

It also allows other default behaviors to work with blueprints, such as:

• automatic parameters from path
• automatic summary from docstring
• ability to pass tags for a whole blueprint: blueprint_three = BlueprintWithSpec(__name__, tags=["tag 1"])

Any comment welcomed!

[jakemwood]

Just released to v0.6.0. 🎉

[philippeauriach]

thanks !