Fix external javadoc URL for commons-io.

- Add correct "proper/commons-io" prefix to no
  longer rely on legacy link redirects
- Add new needed path segment "/javadocs/"

See:
https://issues.apache.org/jira/browse/IO-369
http://svn.apache.org/r1451593


git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1454828 13f79535-47bb-0310-9956-ffa450edef68
Add info about failing charset to unit test.


git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1454832 13f79535-47bb-0310-9956-ffa450edef68
Fix failing unit tests

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1454839 13f79535-47bb-0310-9956-ffa450edef68