Return false for empty list

[garrensmith]

Overview

Currently if we have a document like this:

doc = {
  name: 'Garren',
  activities: []
};

and then create a selector like this:

find({selector: {
   activities: {
      $allMatch: {
        ['fishing', 'golf']
     }
   }
});

CouchDB mango will return the above document. This doesn't seem correct since it doesn't actually match the $allMatch selector. This PR changes that so that an empty document is false.

Testing recommendations

There is an additional test added to the Mango tests to prove this works.

Checklist

• Code is written and works correctly;
• Changes are covered by tests;
• Documentation reflects the changes;
• I will not forget to update rebar.config.script
  with the correct commit hash once this PR get merged.

[davisp]

+1. $allMatch hasn't been released yet so this is fine to change without version worries.