Update README.

Added an explanation of pull request policy to the README. All significant changes and new features should be submitted to the dev branch only.
Update README.md

Remove cheesy stage play phrasing.
Fix bug in sample app project.
OSKEmailActivity & OSKSMSActivity can publish items with attachments, but no text.
Adds missing Google Plus activity import
Merge pull request #52 from inb4ohnoes/master

Adds missing Google Plus activity import
Merge pull request #51 from samingle/master

Allow email and SMS activities to publish when they have attachments but no text.
Merge with master.
Update sample app.