Added a new descriptive_statistics method in the DescriptiveStatistics module, which returns a hash containing the common values considered to be part of "descriptive statistics."
Also added the associated tests."
Adjusted rakefile to use Rake::TestTask to run tests. Also removed the puts statment from test_descriptive_statistics... it was there for debugging.
Updated the README.md to contain a description for the descriptive_statistics methed and added myself (Graham) as a contributor. In addition added a test to prove that percentile(50) is, in fact, the median.
Added myself in the list of authors for the gemspec. I did not update the date, or the version number.
Merge pull request #10 from graham-malmgren/master

Added descriptive statistics method returning hash