[Review] Request from 'digitaltom' @ 'SUSE/connect/review_140430_add_activation_for_non_base_products'

Please review the following changes:
  * 6c3df09 - enable activation of non-base products - proper handling of argv - don't log to stdout when testing
  * a937d40 add docs, fix tests
  * e180c9d Merge pull request #69 from lslezak/sha256
  * 71f6eda improve error messages in connect cli
  * ce43115 added method for computing SHA256 fingerprint
  * ccba677 don't try to register without regcode