668 C# Generator Changes

[baseTwo]

Work for #668

C# Generated Code

1. Implement ILibrary as explicit in the C# generated code - so that they don't conflict with potential generated members
2. Place regions around code blocks
3. Remove the UTF8 Byte Order Marker (UTF-8 uses 1-byte code units, so there is no need for a BOM to indicate a byte order, because there is only 1 byte order possible, and the encoding algorithm determines the ordering of the bytes.)
4. Fix generated tuple properties (See below TupleMetadataBuilder)

C# Generator

1. Remove the exception handling callback
2. Remove the callback for converting library name to class name. Use the VariableNameGenerator directly
3. Rename LibrarySetDefinitionsToCSharpCodeProcessor to LibrarySetCSharpCodeGenerator
4. Rename LibraryDefinitionToCSharpCodeProcessor to LibraryDefinitionCSharpCodeGenerator
5. Rename IndentedWriter to IndentedTextWriter
6. IndentedTextWriter to use the base type TextWriter instead of StreamWriter
7. Upgrade version to 2.0.10

TupleMetadataBuilder

1. The tuple metadata properties must be sorted alphabetically, to reduce changes when comiting to the repo
2. Only generate the necessary tuple metadata properties that are needed for the particular library

MSBuild

1. Remove the Generate-CQL-to-ELM and FullDebug build targets
2. Add MSBuild variables in the props files for enabling building ELM (CqlToElmEnabled) or C# (ElmToCSharpEnabled)
3. Update .Targets.xml files conditions for these new variables