Widget signatures, certificates and initial scripts for creating them.

The 'create-signatures.sh' script doesn't work, but the
'create-certs.sh' seems to.  The example certificates are
included to make 'create-signatures.sh' work, but could be modified.

Jira issue: APPPR-9
Updated widget creation scripts and signatures as examples.

The new scripts do better error handling and are renamed for
consistency.  The Readme files have been updated as well.

Jira issue: APPPR-9
Merge pull request #5 from jplyle/APPPR-9-Widget-Signatures-And-Example-Certificates

Apppr 9 widget signatures and example certificates