Rename Artifact Ids. Fixes #33

This makes them follow the convention most projects use, and makes it
less confusing to reason about when looking at dependency JARs in an IDE
or a build.

core -> lightblue-client-core, http -> lightblue-client-http
Remove setters from LightblueRequest interface. Fixes #25
Merge pull request #39 from derek63/fixinterface

Remove setters from LightblueRequest interface. Fixes #25
Merge pull request #34 from kahowell/master

Rename Artifact Ids. Fixes #33