Add support to embed videos.
Raise better IOError if a connection file is not found

when starting parallel.Client

Example:

    IOError: Connection file u’~/.ipython/profile_default/security/ipcontroller-client.json' not found. Is a controller running?
Add is_complete request and reply to messaging infrastructure
Expose IPython machinery for testing code completeness
Document is_complete messages

Also, bump message spec version
Four possible states for completion reply, & indent hint
Set protocol version number back to 5.0

Bumping to 5.1 wasn't necessary, because we're still finalising 5.0
(thanks @minrk)
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
add tests for file download via ContentsManager
Merge branch 'serve-from-cm' of github.com:manuelRiel/ipython into serve-from-cm
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