Update Apache Commons Lang (2.6 → 3.4)

This task is to update the version of commons lang libarry to the latest version.

• http://commons.apache.org/proper/commons-lang/article3_0.html

• http://commons.apache.org/proper/commons-lang/release-notes/RELEASE-NOTES-3.4.txt

It looks like even if 3.0 is not completely backward compatible, most of the work can be done by just replacing the corresponding import statements. All features that were removed seem to be covered by Java anyway.