Merge pull request #27 from kliph/2013-08-uwmadison

fix typo
Added combined lesson writing code for people
Merge remote-tracking branch 'upstream/2013-08-uwmadison' into 2013-08-uwmadison
Added combined lesson dont repeat yourself
Added ipython intro lesson
Remove ipython content from writing_code_for_people

The ipython content is now covered in the ipython lesson.
Add hello.py to ipython intro directory
Add condition & emphasis on code readability

Conditional section is copied from dont repeat yourself / flow control.
Emphasized code readability considerations for variable name & type
choice, white space and comments.
Remove conditional section
Add whtespace to summary
working on PR exercise
changed names to a and b
added pr exercise
Add pasting help, docstring emphasis, minor changes
Added Set content back
finished initial remote work
final revisions
whoops, forgot the ipython numbering
final note on the extra credit section
updated repo names