provide config for editorconfig plugins

* If a dev adds an editorconfig plugin to their editor,
  automatically configure their editor for code style.

* Specify 4-space softtabs so new code will be compatible
  with Python 3.

* Put the same settings in .gitattributes so git diff
  highlights whitespace errors.
add pep8 tests for syntax errors
add pep8 tests for deprecated python usage
add pep8 tests and fix whitespace errors and warnings
add pep8 tests and fix blank line errors and warnings
add pep8 tests for import errors
add pep8 tests and fix statement errors
add pep8 tests and fix redundant backslashes between brackets
add pep8 tests and fix lexical indentation for python3

These are the pep8 tests that break python3,
such as mixing tabs and spaces for indentation.

I ignored all the pep8 tests that seemed only stylistic,
such as "visual" indentation.

http://docs.python.org/3.3/reference/lexical_analysis.html
exceptions are now compatible with both python 2.5 and 3.3

The syntax for capturing exceptions changed in python 3, but
we need to continue supporting python 2.5 syntax since many
people use tito on RHEL 5, which has python 2.5.

http://docs.python.org/dev/howto/pyporting.html#capturing-the-currently-raised-exception
add modules compat lib to support both python 2 and 3

Tito uses two modules that have changed significantly between
python 2 and 3:

* commands module merged into subprocess module
* ConfigParser module renamed as configparser
add unit test and use print function for python3 compat

Python 3 does not have the print statement, so convert all
print statements to print functions and add an ugly duckling
unit test to detect regressions.
add python 3.3 to travis-ci build matrix