Add partial search functionnality

hey @sethvargo

I modified `ChefAPI::Connection#request` to handle query params with `#patch,post,put` in the first commit.
I did not see any unit test to modify.
On the other hand, my app create, modify and delete clients, nodes and environments.
We dont see any bugs or backtrace with these modifications.

So, I add partial search ! And a test for the partial thing obviously :smile: