If needed unescape a type AssemblyQualifiedName

A type AssemblyQualifiedName need to be un-escaped when it contains the `\` character. That's pretty uncommon but looks like:

    @"TypeA`2[[System.Collections.Generic.List`1[[TypeB, AssemblyA, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null\]\], mscorlib, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e][TypeC, AssemblyA, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]], TypeD, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"

[1] http://msdn.microsoft.com/en-us/library/system.type.assemblyqualifiedname.aspx