Deprecate #IfAny since #if works just as well.

The only usage in kss-node was {{#ifAny markup modifiers}} and, since modifiers
is an object and, always evals to true (even when empty), #ifAny was effectively
a dupe of Handlebars' built-in #If.
Deprecate "html" handlebars helper in favor of triple-stash.
Deprecate whenDepth in favor of ifDepth and unlessDepth.
Move deprecated ifAny next to other deprecated helpers.
Merge pull request #74 from kss-node/deprecate-ifAny

Deprecate #IfAny, #whenDepth, {{html expr}} in favor of #if, #ifDepth, {{{expr}}}