Merge tag 'v0.5.4' into experimental

Version 0.5.4
Restored experimental info/dependencies
Scans: Show error message when the full report could not be retrieved

[Closes #78]
Scan#save_report_and_shutdown: Log errors during report retrieval

[Issue #78]
Bumped version to 0.5.5
Gemfile: Set Arachni to v1.0.4
Merge branch 'release/v0.5.5'