The Office 365 Development Patterns & Practices team have shipped the new open source repository today to GitHub.com/OfficeDev. The whole idea of releasing this is that, many sharepoint developers were familiar with how to build custom solutions with full-trust code and VSTO, however they did not know how to implement these solutions using App Model. The set of samples addresses the transformation from Full Trust Code to App Model.
The additional content for Office 365 development is available in Microsoft Download Center SharePoint 2013 and SharePoint Online solution pack for branding and site provisioning.