Bump changelog to RC4

Install certbot packages in postinstall script

Merge pull request bluecherrydvr#464 from bluecherrydvr/buffer_append…

…_fix

Fixed buffer append crash

Update 3.1.0-RC1 release notes

Fix formatting in changelog, resulting in build scripts freaking out.

Update changelog for 3.0.6

Merge pull request bluecherrydvr#427 from bluecherrydvr/groovy-support

Add Ubuntu Groovy support

Update changelog for v3.0.4

fix db upgrade failure, add executable bit to upgrade script