[BREAK] HTTP Datasource: default lookup_key false (#135)
[BREAK] HTTP Datasource: default lookup_key false (#135)

* bumped version to 3.0.0-pre4

* [BREAK] HTTP Datasource: default lookup_key false

As per the documentation and comments, lookup_key is changing
to a default value of false in Jerakia 3.0 - this is mainly
due to the limited flexibility offered by the HTTP datasource
in digging into data structures using lookup_key - which expects
the top level keys of the returned hash from the HTTP end point
to be the same as the request keys... This is rarely enough
The better way of doing this is to set `lookup_key` to `false`
and use the `dig` filter in the lookup which is far more
flexible.

crayfishx/jacaranda