Document how to build the system

Currently the description covers:
  * Windows 2008R2
  * Mac OSX Mavericks
  * SmartOS containers running
    - CentOS 6
    - Ubuntu

Change-Id: If3116beb31430d8d88ab5241fd6bfaa251e89b3c
Reviewed-on: http://review.couchbase.org/35552
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>