Improvements to Windows setup

1. The current structure and phrasing caused several students to try
   to either only install the SWC Windows installer, or try to install
   it before installing one one of it's dependencies.

2. We discovered an edge case where a user tried to run the
   installer without an internet connection which causes an error
   since nano can't be downloaded.
Remove discussion of ls -s and -h

This material doesn't seem to me to accomplish a lot with respect
to the objectives of the lesson and it adds a feeling of "the
shell is complicated" right up front by talking about how the
default output is confusing, showing a "human" flag that
presents things in bytes (which isn't *that* human friendly for
novices), and discussing how memory works.
Added "Parallel programming with the multiprocessing library" lesson
Adding pointer to installation/configuration wiki page
Add the use of ls -s -h as an exercise
Merge pull request #412 from ethanwhite/remove-ls-details

Remove discussion of ls -s and -h
Merge pull request #421 from gvwilson/adding-link-to-config-wiki

Adding pointer to installation/configuration wiki page
Add link to older installers for Git for OS X

The current Git installer for OS X is broken for many pre-10.8
systems. The older installers seem to solve this problem.
Merge pull request #425 from ethanwhite/mac-setup

Add link to older installers for Git for OS X
Updated multiprocessing lesson to reflect reviewer comments
Addressed additional reviewer comments.  Ran through ispell.
Add a section on pickling
Merge pull request #1 from khinsen/multiprocessing

Add a section on pickling
Fixed grammatical typo
Changed the order in which parallel code is described to begin with
defining the work to be done (which follows the order in the complete
example source code)
Resetting unintended changes
Tell people what to type into the mars.txt file.
Merge pull request #434 from mkcor/anthonyandmarianne

Anthony and Marianne added an entry for "library" in the glossary
Merge pull request #436 from dtrap/01-backup_fix

Tell people what to type into the mars.txt file.
Merge pull request #417 from selimnairb/master

Added "Parallel programming with the multiprocessing library" lesson