Updated obsolete references
Completed list of builtincontenttypes
Added Client Secret Expiration
Added support for V15 CSOM SDK
Adding Core.RibbonCommands sample
Merge branch 'dev' of https://github.com/OfficeDev/PnP into dev
Add Workflow.AssociateToHostWeb sample solution
Merge pull request #176 from erwinvanhunen/V15Support

Added support for V15 CSOM SDK
Merge pull request #173 from erwinvanhunen/CoreFixes

Renamed obsolete references
Update readme.md
Added information about the option to enlarge the client secret enddate to today+3years