add Application.launch_new_instance classmethod

allows uniformity when making changes.

The change here that prompted it is passing arguments to the instance constructor and initialize.
use launch_new_instance classmethod to launch apps
add IPython.start_ipython

A public API for starting a real (non-embedded) IPython instance.

should avoid API breakage in the future due to simple module renames

as has just happened with the removal of frontend
expand start_ipython / embed docstrings

clarify the difference between them.
add IPython.start_kernel

for symmetry
Application.launch_instance

removes `new` from method name, since it isn't accurate.
use start_ipython in entry points

increases visibility of the public API to snoopers.
remove extra empty lines
notebook supports raw_input and %debug now

updates Frontend-Kernel model example notebook to reflect this.

closes #3489
add 'No Checkpoints' to Revert menu

when there are None, rather than an empty menu.

closes #3261
update CodeMirror component to 3.14

I believe this closes #3361, if @fperez and/or @fonnesbeck can confirm.
use `isoformat()` in jsonutil

allows preservation of timezone info.

Timezone info is still ignored in the extract-dates part, for now.
add IPython.utils.tz

Basic support for tz-aware UTC methods on date time objects.

The raw `utcfoo` methods still produce naïve objects,
so they are wrapped in a simple zero-offset tz-aware object.

This allows jsonutil to publish the timezone info,
eliminating the ambiguity of naïve timestamps (Firefox assumes local time, WebKit UTC).
add timezone info to `last_modified` in notebook managers

now Firefox won't get confused, turning utc timestamps into local times.

closes #3396
allow just the trailing Z for timezone
ensure 'default' is first in cluster profile list

when sorting, `'default'` is transformed to `''`.
tweak regexp handling of tzinfo

allows for excluding the 'Z' from the timezone info
test jsonutil handling of dates
include nbconvert templates in installation

fixes path spec in setupbase.py:find_package_data
remove debug statement

and anchor