Templates are registered globally in a search path as a form of subclassing
and overrides.  Thus each blueprint must specify a different path.  To
avoid "blueprint/templates/blueprint/xxxx.html" I stuck all templates here.

http://stackoverflow.com/questions/22190881/flask-multiple-blueprints-interfere-with-each-other

which links to

http://stackoverflow.com/questions/7974771/flask-blueprint-template-folder/8198325#8198325

Just shoot me.
