support static members/methods in an interface

[aidinabedi]

JSDoc allows members (like functions and variables) to be static inside an interface (or mixin). Currently, this will generate invalid TypeScript. This PR fixes that by moving all static members to a namespace (which has the same name as the interface) and thus performs a namespace merge.

So the following JavaScript:

/**
 * @interface
 */
function Color() {}

/**
 * @function Color.staticMethod1
 * @static
 */
Color.staticMethod = function() {};

/**
 * @member {Number}
 * @static
 */
Color.staticMember = 1;

/**
 * @function
 */
Color.prototype.instanceMethod = function() {};

/**
 * @member {Number}
 */
Color.prototype.instanceMember = 2;

Will generate the following TypeScript:

declare namespace Color {
    /**
     * @function
     * @static
     */
    function staticMethod(): void;
    /**
     * @member {Number}
     * @static
     */
    var staticMember: number;
}

/**
 * @interface
 */
declare interface Color {
    /**
     * @function
     */
    instanceMethod(): void;
    /**
     * @member {Number}
     */
    instanceMember: number;
}

Which is perfectly valid TypeScript.

[aidinabedi]

Fixed conflicts.