(docs) add workerpath sample to readme

[ciel]

This update adds instructions for using the new workerPath property to circumvent problems that ace encounters when using bundled, concatenated, minified, and uglified sources.

Support for concatenated bundles

Trying to use ace with concatenated javascript files usually fails because it changes the physical location of the workerPath. If you need to work with bundled or minified versions of ace, you can specify the original location of the workerPath on disk (not the bundled file).

This should be the folder on disk where ace.js resides.

<div ui-ace="{
  workerPath: '/path/to/ace/folder'
}"></div>