Document how Assertions and Post-Processors handle sub-samples.
Document how Assertions and Post-Processors handle sub-samples.

git-svn-id: https://svn.apache.org/repos/asf/jakarta/jmeter/trunk@671147 13f79535-47bb-0310-9956-ffa450edef68

Former-commit-id: 74809c1b9234e8fb94f9f262050ce44984c6ff3c
benbenw/jmeter,apache/jmeter,etnetera/jmeter,apache/jmeter,etnetera/jmeter,ham1/jmeter,benbenw/jmeter,apache/jmeter,ham1/jmeter,etnetera/jmeter,ham1/jmeter,etnetera/jmeter,benbenw/jmeter,etnetera/jmeter,apache/jmeter,ham1/jmeter,apache/jmeter,benbenw/jmeter,ham1/jmeter