Updating cache model
Updating token cache tests and adding new notification BeforeWrite
Fixing WinRT cache based on local settings
Updating tests
Adding cache to AcquireTokenByAuthorizationCode
Returning IdToken in result.
Throwing exception if federation metadata is null in user realm discovery
Adding token cache tests
Merge branch 'dev' into newcache

Conflicts:
	src/ADAL.Common/AuthenticationContext.cs
	src/ADAL.Common/OAuth2Response.cs
Addressing code review comments
Merge pull request #28 from MSOpenTech/newcache

New token cache model