Limit latex equations to page width.
Fixed latex template to support multicol w/ adjustbox.
send idle/busy on all shell messages

Instead of just those that execute code.
This means that kernel_info_request triggers busy/idle,
allowing clients to check IOPub channel status without executing code.
make CORS configurable

allows setting CORS headers.

- cors_origin sets Access-Control-Allow-Origin directly
- cors_origin_pat allows setting Access-Control-Allow-Origin via regular expression, since the header spec itself doesn’t support complex access[1]
- cors_credentials sets Access-Control-Allow-Credentials: true

To allow CORS from everywhere:

    ipython notebook —NotebookApp.cors_origin='*'
Set axis background to transparent in inlinebackend

Fixes #5727, related to #4608
s/cors_/allow_/

add notes about Tornado 4, and comments, updates per review
set busy/idle around every message

not just shell
Fix NaN warnings and failures in test_serialize

don't use empty, which can create a bunch of NaNs,
causing equality tests to fail.
Updated license to include CC BY 4.0 for documentation, examples, and other materials
Added examples to BSD, and added links to online versions of CC-BY
Moved the list of links of the CC-BY licenses below (I could not get RST to render correctly)
allow unicode keys in dicts in json_clean
don’t modify dict keys while iterating through them

in jsonutil.rekey
Remove some unhelpful info from IPython.core.completer
Add docstring for dict_key_matches
test rekey modify-in-place
persist notebook server cookie secret in security dir

prevents loss of login after relaunching the notebook server

closes #6075
Update bundled copy of pexpect to 3.3

Closes gh-6086
Merge pull request #6083 from takluyver/completer-docstrings

Some docstring improvements in completer
Merge pull request #6081 from minrk/rekey-inplace

don’t modify dict keys while iterating through them