Merge pull request #57 from spacecowboy/master

Add concordance index function
odd encoding in doc string
Add utf-8 encoding string to files

Signed-off-by: Jonas Kalderstam <jonas@kalderstam.se>
Update tests for Python3 and requirements.txt

With numpy 1.8.1 at least, the tests will fail if using pandas 0.14. The
tests pass with 13.1 however.

Signed-off-by: Jonas Kalderstam <jonas@kalderstam.se>
Added travis-ci config

Was tricky to make it work with both python 2 and 3 since travis has
some troubles with their virtualenv under python3, hence the manual
virtualenv stuff in the script.

This will actually build numpy, scipy and pandas from source on each
build, and this takes around 30 mins.

Signed-off-by: Jonas Kalderstam <jonas@kalderstam.se>