* Throw error for unknown condition fields as well
So if 'foo' is not a field, refuse to save a template containing
`{{#foo}}bar{{/foo}}`. Previously, only `{{foo}}` would be checked.
As a side effect, templates which *only* contain fields as conditions
may be saved. Meh.
* Display template errors in q/a columns only
So the affected browser row remains active and the user can fix the
template more easily.
* Specify if error occured in a browser template
* Minor wording tweak (dae)
There's an argument for using the exact wording as well, but this just
reads a little more naturally to me.
