Annotations are just string maps, but to render those we need a bit more information (is it a link, should it be visible by default). Store them as more complex structs internally, this also allows us to drop alert.Links since we now have enough information to tell if annotation is a link
Internal packages are supported by Go 1.5+, any package in /internal/ dir is only importable from the same repo. This will cleanup main dir a bit and provide better namespace for unsee subpackages
