Introduce the tech deep-dive document of the oBIX 1.0 release

This document provides insightful views of the design on the following
part of software:
. the Modbus Gateway Adaptor;
. the History Subsystem of the oBIX Server;
. the Watch Subsystem of the oBIX Server;
Merge pull request #11 from Qingtao-Cao/devel

Introduce the tech deep-dive document of the oBIX 1.0 release