Tidy; add usage comments
Tidy; add usage comments

git-svn-id: https://svn.apache.org/repos/asf/jmeter/trunk@1339078 13f79535-47bb-0310-9956-ffa450edef68

Former-commit-id: c932ee6a299054bffac04872edaf7b812d9f6f5e
apache/jmeter,etnetera/jmeter,apache/jmeter,benbenw/jmeter,apache/jmeter,benbenw/jmeter,ham1/jmeter,etnetera/jmeter,etnetera/jmeter,etnetera/jmeter,ham1/jmeter,etnetera/jmeter,ham1/jmeter,benbenw/jmeter,apache/jmeter,ham1/jmeter,benbenw/jmeter,apache/jmeter,ham1/jmeter