IPython Console: Remove unneeded imports
IPython Console: Uncheck and disable auto_refresh_button from Variable Explorer for its clients

Update Issue 1450
Status: Started

- When auto_refresh_button was active, our IPython kernels consumed more and
more CPU during time in a dramatic way! After just three hours of being idle,
they were using about 30% of CPU.
- This has an important side effect: now we are forced to refresh the Variable
Explorer after each cell execution (but that's probably what most people
intuitively expect).
PySide compatibility: We were unable to create an IPython client if using IPython 2.0dev

- The problem was with changing %edit before setting the __ipythonkernel__ global
in start_ipython_kernel.py.
- It seems changing %edit was taking too much time and that prevented the
monitor to find __ipythonkernel__ in the namespace. Without it it couldn't know
that the kernel was started.
Merge from 2.2 (Possible fix for Issue 1450)

- Also fix being unable to create IPython clients when using PySide and IPython
2.0dev.
IPython Console: Remove grey background of inline images for IPython 1.0+
IPython Console: Change pylab banner message for IPython 1.0+
External Console: Don't use our scientific startup script for IPython kernels

- Using scientific startup was contradicting the option we have on the IPython
console to not import numpy and pylab when matplotib support is active.
Merge from 2.2 (Several fixes for IPython Console)
IPython Kernel: Simplify function to change %edit to use open_in_spyder
IPyhon Kernel: Make %pylab load numpy and pylab even if the user has set autoload_pylab to False
IPython Console: Add (again) an option to change clients background color to be dark

Update Issue 1520
Status: Fixed

- Thanks to phyo.arkarlwin for the help.
- phyo suggested a much easier way to do it than what I did before (which
required subclassing IPythonQtConsoleApp).
Merge from 2.2 (Add an option to set dark background to IPython consoles)

- Also make %pylab to load numpy and pylab even if autoload_pylab is off.
bootstrap.py: Add a --test option to be able to test Spyder with a clean settings dir

- This can spot errors that otherwise would go unnoticed (for example revision
1a6344bc0259).
Merge from 2.2 (Add a --test option to bootstrap.py)
Check if DEV variable is None or not on all instances is called
PySide compatibility: Show IPython Console on first run (if available)

- Sometimes the plugin was not auto-shown when trying to open a console, which
was quite confuse for people.
- This also shows that IPython is available under Spyder (which people
sometimes doesn't know!).
PySide compatibility: Backport revision 4f523daf4159

- Although much less frequent, I've also seen the error reported on that
revision in this branch.
PySide compatibility: Avoid an OverflowError when trying to drag and drop tabs around
Merge from 2.2 (Various PySide compatibility fixes)