Add Layer.image type check

framer/Layer.coffee

@@ -479,6 +479,9 @@ class exports.Layer extends BaseClass
			@_getPropertyValue "image"
		set: (value) ->

			if not (_.isString(value) or value is null)
				layerValueTypeError("image", value)

			currentValue = @_getPropertyValue "image"

			if currentValue == value

test/tests/LayerTest.coffee

@@ -129,15 +129,25 @@ describe "Layer", ->
			layer.properties.image.should.equal imagePath

		it "should set image", ->
	
			imagePath = "static/test.png"	
			layer = new Layer image:imagePath
			layer.image.should.equal imagePath

			layer = new Layer y:0, \
				x:0, y:0,
				width:100, height:100,
				image:imagePath
		it "should unset image with null", ->
			layer = new Layer image:"static/test.png"
			layer.image = null
			layer.image.should.equal ""

			layer.image.should.equal imagePath
		it "should unset image with empty string", ->
			layer = new Layer image:"static/test.png"
			layer.image = ""
			layer.image.should.equal ""

		it "should test image property type", ->
			f = ->
				layer = new Layer
				layer.image = {}
			f.should.throw()

		it "should set name on create", ->
			layer = new Layer name:"Test"