Signature creation script creates valid distributor signatures names.

Jira issue: APPPR-9
Fix bugs in widget signing and add support for Paddy's signing tool.

There were a couple of bugs in the signing scripts, those are now fixed.
There's now a script using Paddy's java signing tool as well.

Jira issue: APPPR-9
Merge pull request #6 from jplyle/APPPR-9-Widget-Signatures-And-Example-Certificates

Apppr 9 widget signatures and example certificates