add new FilesHandler to serve files from ContentsManager.
add new FilesHandler class
add tests for file download via ContentsManager
mark binary properly as binary for python 3
get bin test file to pass. (2nd try)
3rd
Use \xFF in bin file test
correctly handle base64 and json, improve bin-file test
make base64 decoding ipython3 compatible
another shot at bin-tests on python3
fix bin-file test in ipython3
2 checks for python2 and python3)
use ContentManagers own is_hidden() function
remove redundant abs_path
remove unused import
remove unused import in test_files.py
simplify bin-file test
remove commented-out code
finish up FilesHandler

- load FilesHandler like everything else
- remove copy/paste leftovers