Add support for hooks and hook for onSearch

[KieranHunt]

Implements: #36

Hey! I wanted to play around with what this API would look like and this is what I came up with. What do you think?

Outstanding questions:

• Is this something that you'd like to add / would think is generally useful?
• What other hooks do you think are missing? I could also see a hook for clicking on a suggestion may be helpful too.
• Do you think I should pass something different to the onSearch hook? I think suggestions could be useful too but I didn't know if you wanted to expose that object in the contract.
• Is this even a good way of doing this? I've very much a Vue novice.