more updates

- increase selenium version to 2.32
- add `wait_for` which waits for visibility/presence of a certain
element
- allow `wait` override locally in kwargs
- allow `highlight` disable
- use `ActionChains` instead of js hackery (same as PR #35)
- add `move_to_and_click` which is different from `click` since `click`
clicks at the center of the element, which is not always desired