Add an S3 print method for prettier console output

This commit illustrates how the return list used for api calls
can be assigned a simple S3 class `github`, such that S3 methods
(any function ending in `.github`) can be added for this class.

I illustrate this with a print method which formats the output
of an API return call in a slightly nicer way. Note that my
output function introduces a dependency on the `yaml` package,
available on CRAN.
add S3methods.R to collate list in Description
Merge pull request #18 from cboettig/master

Add an S3 print method for prettier console output
temporarily revert class setting until we remove yaml from requirements
Merge branch 'hotfix-ignore-badgithub-withbody'
merge
revert yaml dependency
adding necessary .travis.yml to master. ?
merge
Merge branch 'develop'
Specify Github API version explicitly

Please see http://developer.github.com/v3/versions/ . From March 15, 2014 the Github API default will switch to `v3` from `beta`. This will break a few things in RCloud, for which the detailed list is here. http://developer.github.com/v3/versions/#differences-from-beta-version 

The proposed change ensures that we explicitly provide `beta` as a specific version until we are ready to move to `v3`.
Merge pull request #22 from smschauhan/patch-3

Specify Github API version explicitly
addded fxn for hitting the contributor stats endpoint
Merge pull request #24 from sckott/contribstats

addded fxn for hitting the contributor stats endpoint
httr 0.3 compatibility. closes #23
verbose mode
Merge branch 'develop'