Add ability to filter snippets by their template.
Stop hiding Client Match Rules on the snippet admin page.

Because Every time I open that section I wish I didn’t have to.
Merge pull request #74 from Osmose/stop-hiding-cmrs

Stop hiding Client Match Rules on the snippet admin page.
Merge pull request #70 from Osmose/filter-by-template

Add ability to filter snippets by their template.
Add the ability to use a checkbox for a boolean template variable.