Mustache sections can only take a boolean or a container (array or map) value

I have an issue with how cfengine handles mustache templates.

The mustache engine renders sections when the value is a boolean or container.
This should be different:

• Render when (key resolves to value AND (value is true OR value is not empty list))
• This behaviour should be negatable by the '^' section attribute

As documented on: http://mustache.github.io/mustache.5.html

Sections
Sections render blocks of text one or more times, depending on the value of the key in the current context.

A section begins with a pound and ends with a slash. That is, {{#person}} begins a "person" section while {{/person}} ends it.

The behavior of the section is determined by the value of the key.

False Values or Empty Lists

If the person key exists and has a value of false or an empty list, the HTML between the pound and slash will not be displayed.

http://mustache.github.io/#demo

Handles the mustache_example.json and mustache_example.mustache as expected; without exeptions.

The following unittest data seems to handle "Context Misses" correctly
core/tests/unit/data/mustache_sections.json

        {
            "name": "Context Misses",
            "data": {},
            "expected": "[]",
            "template": "[{{#missing}}Found key 'missing'!{{/missing}}]",
            "desc": "Failed context lookups should be considered falsey."
        },

The following acceptance test expects the error "Mustache sections can only take a boolean..." to be thrown.
core/tests/acceptance/10_files/templating/mustache_section.cf

I have attached a diff. After applying:

• rebuild dir core/libutils
• rebuild dir core/libpromises
• replace/link libpromises.so