Update changelog for 1.1.5 release

Also updated NuGet packages for managed E2E test app
[Managed E2E Test App] Update project files
[JS E2E Test App] Update SDK to 1.1.5
[iOS E2E Test App] Updated to latest SDK
Merge pull request #188 from carlosfigueira/dev

Update changelog and E2E test apps for 1.1.5 release
Fixed expired certificate error for Win8 test project
Fix references in sample projects that are part of the Xamarin Component
Updated Win8 and WP8 quickstart to use latest version of our SDK, dropping the dependency on the async nuget package
[WinStore E2E Test App] Add tests for offline feature
Merge branch 'offline' of https://github.com/carlosfigueira/azure-mobile-services into offline