py3: Updates FileDataset to allow proper file reading and successful filereader unittests
py3: Updates FileDataset to allow proper file reading and successful filereader unittests

Python 3.x now utilizes io.BufferedReader by default. Changes made to dataset.FileDataset to
ensure that the proper filetype_obj was passed to filereader.read_deferred_data_element in
the case where the object provided is an io.BufferedReader instance.

Additionally, 2to3 was unable to properly convert several zip instances so they had to be manually
converted to lists which is backwards compatible as well.

All unittests currently in test_readfiles.py pass in python 3.2.3 after 2to3 conversion.

carlomt/dicom_tools,carlomt/dicom_tools