5.0.1.631 Token location refactoring, Serialization refactoring and addition of Xml & System.Text.Json value converter

• Refactored indexing.
  • The new indexing does always include ranges within the template and are more verbose.
  • Tag Document items do now have information on the start and end of the whole tag embedded
  • Block Document items have a new property BlockLocation that mark the closing tag of that block
• Refactored XML and Json serialization.
  • Json serialization does no longer depend on the TypeNameHandling = TypeNameHandling.Objects setting from newtonsoft as it adds its own Type Discriminator
  • Added support for System.Text.Json serialization
  • Added support for Nullable type serialization.
• Added additional Number.cs formatters such as "IsIntegralNumber", "IsFloatingPointNumber", "AsFloatingPointNumber"
• Added support for Numbers to be used with #REPEAT blocks
• Added additional Linq formatter
• Breaking Change: Updated Inheritance for Block/Tag document items. Only block documents now declare a Children property.