replaced apache's commons-io with google's

* had problems with unknown methods in different IDEs, as nowhere
  explicitly imported with version. as google's io was imported
  anyway, using this.
removed redundant itext version spec
pdfbox version to release

* pdfbox had 'rolling' snapshot version, that happened to break
  the build from time to time. now switched to 1.8.6 release version.
flint-hadoop: copyFromLocalFile with more params

* at my computer (Win7, once installed cygwin) the tests were failing
  complaining similar to http://tinyurl.com/mmvas9g; not sure whether
  it's a general issue or only with cygwin installations?