Correct "Build Now" and "Build with Parameters" buttons.

### Summary

Attempts to fix #5 by:

- Adding a `getButtonInfo` function which returns normalized button key/values (i.e. innerHTML, href, hasParams?).
- Following same approach as links in that there is a simple `onclick` vs. `jQuery.click`.
- Delegating to the Jenkins intrinsic `Ajax.Request` for dispatching request.
- Using `hoverNotification`.

### Screenshots

#### Job With Parameters

![](https://cloudup.com/ccvsliC8rY8+)

#### Job With Parameters...Next Page

![](https://cloudup.com/cdsTQ1frWrj+)

#### Normal Job

![Build Now](https://cloudup.com/cHxJmQ3mRlP+)

#### Normal Job after Click

![after click](https://cloudup.com/cmu2dJCA3LE+)