added utility methods

added store

fixed bugs and updated samples

updated README

changed userAgent string
moved Store into client module
Merge pull request #13 from evernote/1.23.1

1.23.1
Added a sample project using Pyramid framework.

Added how to use pyramid sample on README.md

Fixed some code lines to follow pep8.

Changed the description about pyramid sample project on README.
Merge branch 'pyramid_sample'