Pasted version from master branch into this branch through web interface

Hi, I am new to GitHub, and I am sure there are better ways of doing this. I was unable to find any way of commenting on files, or propose merging a file from one branch to another, without first creating my own fork and manually copying contents from one branch to another to get an appropriate changeset.

What I want to suggest is that the mcs/class/WindowsBase/System.IO.Packaging/PackagePart.cs file of the master branch is merged into the 3.2.6 release branch, as the master version of the file fixes an XML bug that prevents EPPlus and similar libraries for creating Excel files from working.

See also: https://bugzilla.xamarin.com/show_bug.cgi?id=14811

Many thanks,

Otto