there's --labels.keep so same should apply to receivers, add new option, tests and fixes as it wasn't working properly
This allows to provide a list of labels that are the only labels allowed in the UI, reversing the logic of STRIP_LABELS. Fixes #170
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
