remove non-functional View.kill method

This method cannot be implemented until engines have local nannies
that can send signals.

closes #2772
P3K: fix DeprecationWarning under Python 3.x (base64.encodestring is deprecated)
Merge pull request #2776 from minrk/rmkill

remove non-functional View.kill method
Merge pull request #2778 from kmike/p3k-deprecations

P3K: fix DeprecationWarning under Python 3.x 
Allow the %run magic with '-b' to specify a file.

The syntax would be:
    %run -d -b file2.py:30 file1.py

to break at line 30 of file2.py when running file1.py.

The old syntax
    %run -d -b 20 file1.py
still works the way it used to.

Suggested by user gozzilli on StackOverflow
(http://stackoverflow.com/questions/14305203/ipython-set-a-breakpoint-in-imported-file/).
Fix bp_file -> filename
Merge pull request #2782 from ellbur/run-breakpoints

Allow the %run magic with '-b' to specify a file.
Add a per cell toolbar.

This add a per-cell globally toggleable toolbar
the main purpouse is to easily edit metadata.

this come with a few example like adding checkbox,
dropdown list, simple button, button with icon...

please see the js-doc of
IPython/frontend/html/notebook/static/js/MetaUI.js
for more info
add utils and docs for metadata UI

add aconvenient utils to generate UI for checkboxes

and use it to generate 3 checkboxes for
new_section
new_subsection
new_fragment
Split metadataui into multiple file

Add example metadata UI into multiple categorized files.
And document how to load it using custom.js.
create metadata-dropdowm-menu generator
use dropdown for slideshow cell-type select
remove slideshow example
add a small default metaui-toolbar

just a question mark which pop-up a small text
enable dropdown preset change
convention, jQuery variable start with $

all this.xxxx = $(...) change to
    this.$xxxx

I'm thinking of potentially doing it also in parameters that are
expected to be jQuery enabled.
rename metaui -> celltoolbar
rename file metaui->celltoolbar
rename _button_list to _ui_controls_list
remove most of the duplicate example