Add overloaded Math methods

Abs, Max, Min
String.StartsWith and String.EndsWith
StringBuilder.Append for objects and StringBuilder.Length setter
List.AddRange method
Xml implementation for iOS (libxml2)
Fix defines for Xml (iOS/OSX)
Using new unsigned byte in Cooper (requires new version of Oxygene)
Using new unsigned byte in Cooper (more code and cleanup)
Fix for rtl.sys namespace
Fix for XmlDocument.FromBinary
Namespace fixes for June 2013 compiler
Merged
HTTP implementation for Cooper
FromPath methods for File/Folder
Fix for string formater
Fix for date formating
Fix for StringBuilder.Append (Cooper)
Temp. workaround for #63151 bug
More code for namespaces support (libxml2)
String.Trim fix for Nougat