Merge pull request #130 from bowman224/master

Add Date.now shim to wait-for-cond-in-browser for non-ES5 browsers
Smaller shim comment
Add queueAddAsync command

When chaining commands, it is sometimes necessary to have an async
command that calls a provided callback when complete. For example:

driver.chain()
  ...
  .queueAddAsync(function(cb) {
    http.get('http://google.com', function(res) {
      if (res.statusCode === 200)
        cb();
      else
        cb(new Error('Failed to reach google.com'));
    });
  })
  ...

This commit adds the queueAddAsync functionality. It may be called with
an optional second argument function that is run synchronously after
the first function completes. This mimics the behavior of all the other
wd methods.
fixed error handling in init method
Merge branch 'queueAddAsync' of github.com:txase/wd
added queueAddAsync test and example
README update
README update
configuration via url package
moved server config to main.js and enabled config via url objects and url strings
Improved configuration via option object.
fixed indexed argument configuration
made code compatible with 0.8
made code compatible with 0.8
Merge branch 'url' of github.com:admc/wd into url
made code compatible with 0.8
Merge branch 'url' of github.com:admc/wd into url
updated comments
Error reporting: Report alert message where available.
imported README from MattiSG branch