Don't reset the readline completer after each prompt

This makes it impossible to setup a custom completer. The comment says that
"we must ensure that our completer is back in place," but I don't see why. All
that does it make it impossible to use a different completer. One can trick
IPython into not doing this by monkeypatching ip.has_readline to False, but
then certain features like multiline editing are no longer enabled.

See https://github.com/davidhalter/jedi/pull/321.
make default language highlight configurable for html
fix test
remove more hard coded layout
split notebook style in 2 files,

app specific/not app specific
recompile css
Use svg by default due to lack of Ghostscript by default on Windows
outputarea.js: Wrap inline SVGs inside an iframe

When multiple inline SVGs are included in a single document,
they share the same parse tree. Therefore, style collisions and
use id collisions can occur and upset the rendering.

This patch wraps each SVG inside an individual iframe, ensuring
that SVG's declarations do not collide.

(The SVG representation is kept as XML and not converted to a binary
format, so I do not think this approach precludes the use of d3.js)

Tested on:
* Chrome Version 29.0.1547.57 Debian 7.1 (217859)
* Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130806 Firefox/17.0 Iceweasel/17.0.8

Closes #1866
SVG scoping must be explicitly enabled by the user

SVG scoping is disabled by default, to enable it the user
must call the core.display.SVG constructor with the scoped=True
keyword parameter.
Fix style and typo
SVG: scoped is passed as metadata

Instead of using a svg class to pass scope information
use notebook metadata.

Suggested by Matthias Bussonnier
Support isolated metadata tag for any content

Any content whose metadata contains an `isolated` tag will be isolated
from the rest of the document.

The current implementation wraps isolated content into an iframe.
Notebook isolated content: fix firefox extra-space issue

In Firefox, if the iframe initial height is set to 0, the reported
scrollHeight is too large. Workaround: set the initial height to 1.
Add casperjs test for isolated SVGs
Fix typo.
Preserve layout for large isolated objects
Set both height and width using css
inverse style.less and app.less
add utils.darwin.disable_app_nap

disables the App Nap energy saving behavior of OS X 10.9.
Requires PyObjC, which is included in System Python,
but not in many other Python installations.

It is pip-installable, but takes ages to compile.

should close #4431
min-width instead of width for prompt

mainly helpfull for nbviewer responsive css to have the prompt
above the code cells, and have the correct width.