Merge pull request #191 from coryb/testing

fix #187
update release to 2.1.42-dev
Convert string formatting to be compatible with Python2.6
Merge branch 'testing' into python26_format
Merge pull request #192 from grahamlyons/python26_format

Allow use of `format` to be Python 2.6 compatible
update release to 2.1.43-dev