add menu to switch between hsplit and vsplit pager

Right now, either hsplit or vsplit must have been used when the widget
was started up.
move paging style switching into console_widget
fix #1814 set __file__ when running .ipy files
enable IPC transport for kernels

in progress, but it works

Config is a bit clumsy, because the interpretation of 'ip' is actually a path when transport is IPC.

Notebook does not yet expose the option, because it's still not well integrated into the rest of the config universe.
add size-limiting to the DictDB backend
fix #1814 set __file__ when running [i]python files through interactiveshell
fix #1814 set __file__ when running [i]python files through interactiveshell
Updating parallel options pricing example.
Added new short key for cell execution
%prun: Restore `stats.stream` after running `print_stream`.

When profiling, the output from `print_stream` is captured so that the
output can be paged. To do so, the `stream` attribute is set to a
`StringIO` object but was not restored after the output was captured.
As a result, the stats object returned by `%prun -r` did not display
any output when calling its `print_stream` method.

In addition, the `pstats.Stats` class has the `stream` attribute for
all currently supported Python versions, so the extra branch of code
can be removed.
Allow toolbar construction in js

Base of allowing a full toolbar construction in js without altering the
html template, and use it to construct our toolbar as example.

still need some work to be totally decoupled.
add maintoolbar file
load maintoolbar.js
correcty inherign the main toolbar
dont use string as dict key, better redability
Use breqn.sty in dvipng backend if possible
Add tests for IPython.lib.latextools
2to3: Apply has_key fixer.
Skip `has_key` when running 2to3.
Make lib.latextools configurable

A configurable class LaTeXTool is added which has the following
configuration variables:

- backends
- use_breqn
- packages
- preamble