Update Javadoc somewhat

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1568555 13f79535-47bb-0310-9956-ffa450edef68
build.xml: Add missing depends on init for compile-main target

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1568556 13f79535-47bb-0310-9956-ffa450edef68