Use "text/template" instead of "html/" to not have HTML-escaping

Otherwise, characters like quotes, less/greater than signs, and
ampersand would get HTML-escaped in the text editor for the pull request
message.
Use `project.SameAs(otherProject)` instead of reflect.DeepEqual

This lets github.project implement its own comparison logic. For
instance, two projects can be the same even though their `Protocol`
values don't match.
Merge pull request #604 from github/no-html-escaping

Use "text/template" instead of "html/" to not have HTML-escaping
Support simple push defaults