Returns a value of property by name from
given object literal AST node

@param {Object} objNode an AST node of an object literal
(node.type is assumed to be equal to "ObjectExpression")
@param {String} name a name of a property to return
function getProperty(objNode, name) {
    for (var i=0; i<objNode.properties.length; i++) {
        if (getKey(objNode.properties[i]) === name) {
            return getValue(objNode.properties[i]);
        }
    }
}