fix(usPhoneNumber): fix validation issues on us phone number

* Fix validation issues

* Add test case for validation of US phone number

Model value is added as a number which ensures it can validate (which
is what this PR is for). I noticed other tests are adding the phone
number as a string (in br-phone.test.js), which probably defeats the
test.

* Fix mixed tabs and spaces which prevents tests from passing

src/us/phone/us-phone.js

@@ -23,7 +23,7 @@ module.exports = maskFactory({
 	},
 	validations: {
 		usPhoneNumber: function(value) {
-			return value.length > 9;
+			return value && value.toString().length > 9;
 		}
 	}
 });

src/us/phone/us-phone.test.js

@@ -52,4 +52,17 @@ describe('ui-us-phone-mask', function() {
 			expect(model.$modelValue).toBe(test.modelValue);
 		});
 	});
+
+	it('should validate a phone number', function() {
+		var input = TestUtil.compile('<input ng-model="model" ui-us-phone-number>', {
+			model: 30112
+		});
+		var model = input.controller('ngModel');
+		expect(model.$valid).toBe(false);
+		expect(model.$error.usPhoneNumber).toBe(true);
+		input.val(3011201034).triggerHandler('input');
+		expect(model.$valid).toBe(true);
+		expect(model.$error.usPhoneNumber).toBeUndefined();
+	});
+
 });