We noticed that currently some open source plugins like SecurityInfo and others upload their artifacts into a protected page. for open source plugins it would make sense to consistently upload builds artifacts publicly

Proposed steps:

• for each open source plugin by Piwik/PiwikPro, in travis.yml, check/add UNPROTECTED_ARTIFACTS=1
• maybe we edit the default travis template and add something like:
  `

  for core developers only: uncomment if this plugin is an open source plugin

  UNPROTECTED_ARTIFACTS=1

  `

the setting is documented in http://developer.piwik.org/guides/tests-travis-extended