Use Carat for Negation

[clumpidy]

In mustache you can use a carat (^) for negation like:

An inverted section begins with a caret (hat) and ends with a slash. That is {{^person}} begins a "person" inverted section while {{/person}} ends it.

• from http://mustache.github.io/mustache.5.html

It would be helpful to be able to do {{^equal variable "value"}}