DocumentFormat.OpenXml 2.8.1

# Changelog All notable changes to this project will be documented in this file. The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html). ## Version 2.8.1 - 2018-01-03 ### Changed - Corrected package license file reference to show updated MIT License ## Version 2.8.0 - 2017-12-28 ### Added - Default runtime directive for better .NET Native support. ### Changed - Fixed exceptions thrown when errors are encountered while opening packages to be consistent across platforms. - Fixed issue on Mono platforms using System.IO.Packaging NuGet package (Xamarin, etc) when creating a document. - Fixed manual saving of a package when autosave is false. - Fixed schema constraint data and standardized serialization across platforms. - Upgraded to `System.IO.Packaging` version 4.4.0 which fixes some consistency with .NET Framework in opening packages. ## Version 2.7.2 - 2017-06-06 ### Added - Package now supports .NET 3.5 and .NET 4.0 in addition to .NET Standard 1.3 and .NET Framework 4.6 ### Changed - Fixed issue where assembly version wasn't set in assembly. ## Version 2.7.1 - 2017-01-31 ### Changed - Fixed crash when validation is invoked on .NET Framework with strong-naming enforced. ## Version 2.7.0 - 2017-01-24 ### Added - SDK now supports .NET Standard 1.3 ### Changed - Moved to using System.IO.Packaging from dotnet/corefx for .NET Standard 1.3 and WindowsBase for .NET 4.5. - Cleaned up project build system to use .NET CLI. ## Version 2.6.1 - 2016-01-15 ### Added - Added hundreds of XUnit tests. There are now a total of 1333 tests. They take about 20 minutes to run, so be patient. ## Version 2.6.0 - 2015-06-29 ### Added - Incorporated a replacement `System.IO.Packaging` that fixes some serious (but exceptional) bugs found in the WindowsBase implementation