Renamed to SequelNet, moved to .NET Standard, -> Nuget

• Moved to .NET Standard
• Removed all Obsolete stuff
• Some internal refactoring
• Renamed to SequelNet
• Distributed through NuGet now

Migration notes:

• Take care of any Obsolete warning from the compiler (With a clean Rebuild you will get them all)
• Remove dg.Sql references
• Add SequelNet, and the appropriate connector from NuGet
• Replace in all files the following:
  • dg.Sql -> SequelNet
  • override void Insert(ConnectorBase conn) -> override void Insert(ConnectorBase conn = null, string userName = null)
  • override void Update(ConnectorBase conn) -> override void Update(ConnectorBase conn = null, string userName = null)
  • override TableSchema GetTableSchema -> override TableSchema GenerateTableSchema
  • ([a-zA-Z_0-9]+)FromDb\(reader\[Columns\.([a-zA-Z_0-9]+)\]\) -> reader.Get$1(Columns.$2)
  • IsNull\(reader\[Columns\.([a-zA-Z_0-9]+)\]\) \? \(([a-zA-Z_0-9]+)\?\)null : Convert\.To(\2|Single|Boolean)\(reader\[Columns\.\1\]\) -> reader.Get$3OrNull(Columns.$1)
  • IsNull\(reader\[Columns\.([a-zA-Z_0-9]+)\]\) \? \(float\?\)null : Convert\.ToSingle\(reader\[Columns\.\1\]\) -> reader.GetFloatOrNull(Columns.$1)
  • IsThisANewRecord = false; -> MarkOld();
  • \.TableSchema\b -> \.Schema
  • DataReaderBase -> DataReader