Support implicitly typed properties

[InfiniteLukeOne]

Consider a view:

<template>
    <input value.bind="data.property1" />
    <input value.bind="data.property2" />
    <input value.bind="data.property3" />
</template>

and a view model:

export class ViewModel {
    data = {
        property1: 'test',
        property2: ''
    };
}

aurelia-template-lint should output a warning that property3 does not exist on implicit type {property1:string, property2: string}.