Communicate MeiliSearch error to instantSearch

[bidoubiwa]

In case of error, MeiliSearch sends it usual body to instantSearch. Resulting to this:

instantsearch.js@4:2 Uncaught (in promise) Error: Uncaught, unspecified "error" event. ([object Object])

We should either stop the return process to instant search or find how to communicate it properly to instantsearch

[EricPaulson]

Seconded. The lack of info this message is providing me while trying to get this set up is costing me a significant amount of time.

[bidoubiwa]

Fixed by #216