swc-windows-installer.py: Setup msysgit to act like *nix systems

* Install `nano` 2.2.6.
* Add `ipython` and `nosetests` command line entry points.
swc-windows-installer.py: Cleanup whitespace
swc-windows-installer.py: Separate requests import from stdlib imports

Python-requests [1] is not part of the stdlib.

[1]: http://docs.python-requests.org/en/latest/
swc-windows-installer.py: Avoid writing nano.zip to disk

It's already in memory, and we're going to use it again immediately.
Avoiding the flush-to-disk is both more efficient, and easier to clean
up.
swc-windows-installer.py: Extract nano directly to the install directory

This is more efficient than "extract to . and then copy".  I also
renamed the install_nano() argument.  The function doesn't care that
we're currently passing the Python script directory; it will work
perfectly well with a different directory in the PATH.
swc-windows-installer.py: Simplify `ipython` wrapper

This matches my system's `/usr/bin/ipython-2.7`, and is the hook
defined in IPython's setupbase.py:

  'ipython%s = IPython.frontend.terminal.ipapp:launch_new_instance'

This should handle the 'notebook' option internally.
swc-windows-installer.py: Use `with` to write script wrappers

From PEP 343.  This gives you automatic file descriptor (file handles
on Windows?) cleanup on errors.  Also use os.path.join() to build the
paths.

[1]: http://www.python.org/dev/peps/pep-0343/
swc-windows-installer.py: Use lists for file content

This allows us to keep the usual Python block indentation while still
producing the appropriate wrapper content.
swc-windows-installer.py: Use the stdlib's urlopen()

This way I can test the script (on Linux, but whatever) without having
to install an additional package.
Merge branch 'windows-installer'

* windows-installer:
  swc-windows-installer.py: Use the stdlib's urlopen()
  swc-windows-installer.py: Use lists for file content
  swc-windows-installer.py: Use `with` to write script wrappers
  swc-windows-installer.py: Simplify `ipython` wrapper
  swc-windows-installer.py: Extract nano directly to the install directory
  swc-windows-installer.py: Avoid writing nano.zip to disk
  swc-windows-installer.py: Separate requests import from stdlib imports
  swc-windows-installer.py: Cleanup whitespace
  swc-windows-installer.py: Setup msysgit to act like *nix systems