Yet another travis release fix
Merge branch 'master' of github.com:KSP-CKAN/CKAN

* 'master' of github.com:KSP-CKAN/CKAN:
  Be more sure of the API key we're using for releases.
  Allow releases to be tagged with lightweight tags.
  Warn if a NetKAN file fails to build, but keep going with the rest.

Conflicts:
	.travis.yml