swc-installation-test-2.py: Add MakeDependency class

On the fairly ancient SunOS 5.10 (January 2005), `make` doesn't
support `--version`.  Looking into the POSIX.2 specs [1], it doesn't
have to.  On FreeBSD [2] and in GNU Make [3], there is a MAKE_VERSION
variable, and the Sun executable has something similar:

  $ strings make | grep MAKE_VERSION
  .MAKE_VERSION

but it just expands to an empty string.

Since reading a makefile from stdin *is* in POSIX [1], we can use that
to test `make` if `make --version` fails.  If we get something for
MAKE_VERSION, use that.  If we get something for MAKE (required by
POSIX [2]), then call that a valid, but unkown, version.

[1]: http://pubs.opengroup.org/onlinepubs/009695399/utilities/make.html#tag_04_84_04
[2]: http://lists.freebsd.org/pipermail/freebsd-questions/2010-October/222214.html
[3]: http://www.gnu.org/software/make/manual/html_node/Features.html#index-MAKE_005fVERSION-1021
[4]: http://pubs.opengroup.org/onlinepubs/009695399/utilities/make.html#tag_04_84_13_08
swc-installation-test-2.py: Document command line arguments
swc-installation-test-2.py: Better error message for unknown checks
swc-installation-test: Return 1 on failure

I doubt anyone will check the exit status for these scripts, but it's
still good to follow conventions.
swc-installation-test-2.py: Add 'virtual-pypi-installer' and 'pip'

Students who need a Python Package Index (PyPI) installer should be
fine with either easy_install or pip [1].

[1]: http://pypi.python.org/pypi/pip
     http://www.pip-installer.org/
swc-installation-test-2.py: Comment out 'mercurial' dependency

There can be trouble detecting the Python package, especially on MS
Windows where the installed version of Python used to run the script
may not know about installed version of Mercurial.  Because nobody is
likely to use Mercurial's Python interface in a SWC class (they'll
probably stick to the command line interface), comment out this
dependency.
setup: Move installation test scripts under setup/

There will be a lot of other stuff in the boot camp repository.  Stay
organized by keeping "how to set up and test your machine" stuff in a
subdirectory.
setup/README.md: Install-testing script care and feeding
swc-installation-test-2.py: Add ipython (script) >= 0.13

And make sure the IPython package has the same minimum version.
IPython 0.12 can't display more recent notebooks.
swc-installation-test-2.py: Handle unparsable versions gracefully

This avoids raising NotImplementedError from my IPython 0.14.dev.  We
don't want to have to start ranking alpha, beta, dev, r6, etc., so
just print the unparsable version and minimum version, and leave it to
the student to decide if their version satisfies the condition.  It's
unlikely that students have such pre-/post-release software installed
anyway.
swc-installation-test-2.py: Add Pandas (pandas) >= 0.8

It's being used in 2013-01-columbia.
swc-installation-test-2.py: Add gedit to virtual-editor

For Gnome users.
swc-installation-test-2.py: Add and_dependencies to Python package setup

Not used by any packages yet, but I'm about to use it for IPython.
swc-installation-test-2.py: Print full DependencyError chain

If a requirement is not satisfied due to an and_dependency or
or_dependency failure, raise a new DependencyError and attach the
original error as its cause (this would be easier if we didn't have to
preserve Python 2.x support).  This way we can print the whole chain
(e.g. virtual-shell failed because sh is not installed), instead of
just the lowest level error.

Also indent the messages, because:

  check for virtual-editor failed:
    or-dependency not satisfied for virtual-editor
    For instructions on installing an up-to-date version, see
    http://software-carpentry.org/setup/
    cause:
    check for Notepad++ (notepad++) failed:
      could not find 'notepad++' executable
      For instructions on installing an up-to-date version, see
      http://software-carpentry.org/setup/

is more readable than:

  check for virtual-editor failed:
  or-dependency not satisfied for virtual-editor
  For instructions on installing an up-to-date version, see
  http://software-carpentry.org/setup/
  cause:
  check for Notepad++ (notepad++) failed:
  could not find 'notepad++' executable
  For instructions on installing an up-to-date version, see
  http://software-carpentry.org/setup/
swc-installation-test-2.py: Add IPython notebook dependencies

You can get a successful IPython import even if you haven't installed
the dependencies you need for viewing notebooks.  This adds explicit
dependencies based on the current listings in IPython's setup.py.
swc-installation-test-2.py: List all causes for or-dependency errors

Also make the and-dependency and or-dependency messages more friendly.
swc-installation-test-2.py: Add long names for virtual-* packages

Give a more user-friendly description of what we're checking for.
swc-installation-test-2.py: Add TornadoPythonPackage for version extraction

Tornado follows Python's example with tornado.version and
tornado.version_info instead of using tornado.__version__.  While we
could parse tornado.version with our usual machinery, take advantage
of the pre-parsed version_info by defining a new class.
swc-installation-test-2.py: Add PathCommandDependency

OS X doesn't believe in $PATH ;).  Work around this heresy by simply
checking for the existence of a characteristic file or directory
(e.g. /Applications/SomeApp.app).  I use the new class to add 'xcode',
'sublime-text', 'textmate', and 'textwrangler' installations.

The location of the Xcode installation depends on your version of OS
X, and the 'xcode' comments show which path is expected for which
version.
swc-installation-test-2.py: Initial EditorTaskDependency implementation

I'm not sold on this idea...