Two-way bound attributes are required in a2j-template

[chasenlehara]

While working on #56, I realized that after running the tests from the CLI, Testee would hang in an infinite loop in Firefox. This was consistently repeatable with this template:

a2jdeps/models/fixtures-author/templates/guide1261-template2112.js

Lines 11 to 29 in 1bc9002

	{ tag: 'a2j-repeat-loop',
	state: {}
	},
	{ tag: 'a2j-rich-text',
	state: {
	userContent: 'User\'s last name <a2j-variable name="Client last name TE" />.'
	}
	},
	{ tag: 'a2j-rich-text',
	state: {
	userContent: `<p><em>Lorem ipsum dolor sit amet, pri ad porro consul
	disputando. Mea tale admodum cu, soluta fuisset per ad. Te omittam
	noluisse consequat vel. Impetus appetere antiopam sit ut, at nec
	inani forensibus necessitatibus. Eu eum appetere facilisis reprimique,
	an sit ignota fierent invenire, duis denique sea an. Sit ceteros
	dolores inimicus ut, nec id tantas delenit phaedrum. Nullam prompta
	sit ne.</em></p>`
	}
	}

@mikemitchel and I noticed this two-way binding of an attribute that was not present in the fixture:

a2jdeps/elements/a2j-template/a2j-template.stache

Line 72 in 1bc9002

notes:bind="childNode.state.notes"

After adding notes: '' to the fixture (see the PR above), the tests would pass and Testee would not get caught in an infinite loop.