added a few tests checking the headers actually being set
track the global config and pass it to the host objects on creation
always use self once it's defined
cleaned up ConnectionPool#getConnections()
added tests verifying the global config is always passed to the host.
Merge pull request #141 from spenceralger/updated_for_138

Updates for #138
added a note to the config docs about the `suggestCompression` setting
Merge branch 'updated_for_138'