Add overwriteChainableMethod utility

[hazeledmands]

Here you go. I ended up storing the original method and chaining behavior in a global object, which makes me feel a bit dirty, but there it is. Not sure how else this could be done without significantly modifying the plugin API.

Ref: #215.

[coveralls]

Coverage remained the same when pulling fe192c5 on demands:overwrite_chainable into 0e560c6 on chaijs:master.

[hazeledmands]

Oops. Karma tests don't pass. Attempting to fix...

[hazeledmands]

There. Forgot to add the new file to components.json.

[coveralls]

Coverage remained the same when pulling 2127525 on demands:overwrite_chainable into 0e560c6 on chaijs:master.

[logicalparadox]

Do you have a SauceLabs account so you can run the full browser test suite? If not you can get an Open Sauce account or I can provide temporary credentials:

// test/auth/index.js
module.exports = {
  SAUCE_USERNAME: "[username]",
  SAUCE_ACCESS_KEY: "[access key]"
};

$ make test-sauce

[hazeledmands]

Right on, thanks :) Running them now.

[hazeledmands]

Looks like they all passed. Never used saucelabs before! I am impressed :)

[logicalparadox]

Comments inline ... let me know your thoughts.

[coveralls]

Coverage remained the same when pulling 576d890 on demands:overwrite_chainable into 0e560c6 on chaijs:master.

[coveralls]

Coverage remained the same when pulling 76ac685 on demands:overwrite_chainable into 0e560c6 on chaijs:master.

[coveralls]

Coverage remained the same when pulling 270f9d9 on demands:overwrite_chainable into 0e560c6 on chaijs:master.

[hazeledmands]

Ping -- what can I do to get this merged?

[vesln]

I'm happy to merge it in, however since @logicalparadox did the initial comments, it I'd prefer to wait for him to do so.