extended roadmap by Partial Updates, SPDY and Batch API

Added:

* Dec 2014
  * Partial Updates
  * SPDY
* Jan 2015
  * Batch API

Rendered version: https://github.com/lfryc/aerogear.org/blob/partial-updates-spdy-batches/docs/planning/roadmaps/AeroGearConflictResolution.asciidoc#020-dec-2014-server-push-partial-updates