Changed some commands to use OfficePnP.Core, added some methods overloads to OfficePnP.Core
Merge pull request #37 from erwinvanhunen/MoveToOfficePnP.Core

Changed some commands to use OfficePnP.Core, added some methods overloads to OfficePnP.Core
Change logging to use System.Diagnostics, with same default logging to console
Default logging only Info and above (not Verbose)
Move to singleton (rather than static) logger, and implement methods for standard .NET framework levels. Also add examples of configuring and using them.
Add remarks on how to turn on trace output
Mark old methods obsolete
Merge pull request #38 from sgryphon/LoggingImprovements

Logging improvements