BugFix for display and restoring post revisions

[ghost]

This pull request addresses the following two issues:

1. Currently when revisions are displayed with SH shortcodes, the content within the shortcodes is shown in an encoded state.
2. When revisions are restored the id of the post is the only thing edited. The content is already encoded regardless of decoding it for display. So restoring a post with SH shortcodes will re-encode previously encoded entities. Multiple restores compounds the effect.