support for @see and @constructor

Hi, I'm not sure sutoiku/jsdox is being maintained since you left a PR some months ago and it never got merged in, but I thought you may be interested in this.

jsdox now supports the `@constructor` tag.  Use it in combination with `@class` like so:

```javascript
/**
 * Filter pseudoclass
 * @class Filter
 * @constructor
 * @param {Object} obj Object representing Filter
 */
var Filter = function Filter(obj) {
  extend(this, obj);
};
/**
 * Sets the current filter to be this Filter
 * @method setCurrent
 * @returns {Function|promise|Q.promise}
 */
Filter.prototype.setCurrent = function () {
  return fogbugz.setCurrentFilter(this);
};
```

The generated documentation will look like:

> class fogbugz.Filter
> --------------------
> Filter pseudoclass
> 
> **Parameters**
> 
> **obj**:  *Object*,  Object representing Filter
> 
> **Methods**
> 
> fogbugz.Filter.setCurrent()
> ---------------------------
> Sets the current filter to be this Filter

Furthermore the `@see` tag is now supported.  This may or may not work anywhere else but GitHub because it relies on certain HTML `id` attributes being set.  But for GitHub anyway, it will automatically create a named anchor for every header.  And jsdox creates headers, so we can link to them.  Using `@see fogbugz.logon` below will link to the `logon` method of the `fogbugz` module:

```javascript
/**
 * @module fogbugz
 */
var fogbugz = {
  /**
   * Manually sets a login token if you have one by some other means.
   * @see fogbugz.logon
   * @method setToken
   * @param {string} token FogBugz API logon token
   */
  setToken: function setToken(token) {
    // stuff emitted for brevity
  },

  /**
   * Logs you into FogBugz based on contents of `fogbugz.conf.json`.
   * @method logon
   * @returns {Function|promise|Q.promise} Promise
   */
  logon: function logon() {
   // stuff omitted for brevity
  }
};
```

If you want to link to a module, jsdox will create a heading called "module foo"; GitHub sanitizes the string value of the header to create the anchor name, so to do that you will write `@see module foo`; likewise if you are linking to a class `@see class Foo`; or a class in a module: `@see class someModule.Foo`.

I have no tests for this written, but I may write them in the near future.  If I do that I'll PR back to sutoiku/jsdox for whatever good that'll do; if it doesn't get accepted I'll contact @sutoiku and perhaps volunteer to take over maintenance of the module.