Change sets for set operators to be more intuitive

Using actual people for these sets makes it much clearer what the
-, |, & and ^ symbols actually mean.
Change sets in about_sets.py so set operators are more intuitive

Using something more human-readable for these sets makes it clearer what -, |,
& and ^ mean.
Merge pull request #28 from Ymbirtt/patch-2

Change sets for set operators to be more intuitive
Mergery
quote fix
Quote fix py3 side of house
Seeing as it's python3, let's use braces for the Set definitions
Added some extra clarifaction on what to do on the test_setattr_intercepts_attribute_assignments koans
fix typo bitbucet -> bitbucket
Fixes issue #35: as of Python 3.3, importing a subfolder without the __init__ method does not raise any exception in test_subfolders_without_an_init_module_are_not_part_of_the_package. Trying to import something from it does the trick.

Signed-off-by: DeK <nofatclips@gmail.com>
Merge pull request #32 from ryanbraganza/patch-1

fix typo bitbucet -> bitbucket
Merge pull request #36 from nofatclips/master

Importing a subfolder without the __init__ method
removed duplicate "the" in comment
Merge pull request #37 from t-kl/master

The the bread part of the sandwich
Update README.rst
Merge pull request #38 from hebbertja/patch-1

Update README.rst
Update python2/koans/about_strings.py

Changed the 'con' to 'can' in the function name line 102.
Respect exit codes when there are still koans left to finish
Merge pull request #39 from robotsmack/patch-1

Update python2/koans/about_strings.py
Merge pull request #40 from brainstorm/master

Respect exit codes when there are koans failing