1. Change package name (rm "datasource")
2. Require injection of OkHttpClient through all constructors, and
remove allowCrossProtocolRedirect/connectTimeout/readTimeout
constructor arguments. The client should be configured with these
prior to injection.
3. Fix code style to be consistent with the project.
4. Simplify call to get contentLength. I'm pretty sure okhttp returns
the correct value when gzip is enabled, so there's no need to check
this in the data source.
5. Misc cleanups.
