Added OkHttp driver to support modern HTTP verbs
JCLOUDS-426. Update Elasticstack vnc password key
JCLOUDS-428: Address Java 8 compatibility nits

Tested with JDK 1.6.0_45, 1.7.0_45, and 1.8.0-ea-b123.
The metadata needs to be ordered for this implementation.
JCLOUDS-416. Add TemplateOptions#networks.

- Adds networks field/methods to TemplateOptions.
- Adds them to children as well for legacy reasons.
- Deprecates CloudStackTemplateOptions#networkIds methods in favor of #networks.
- TODO: Modify compute abstraction layer for provisioning for nova,
    EC2, et al to take advantage of this.