Cleanup and overhaul (#21)

* Syntax cleanup

* More minor cleanup, use Linq

* Fix broken features by using correct values

* Feature flags the same

* Features are modular

* No AlphaFS, more .NET versions

* Fix appveyor

* Put back identifiers, for some reason

* String interpolation, modernization

* Better use of GetField

* XmlTextWriter to remove possible issues

* Fix header for OpenMSX

SabreTools.Library/Help/TopLevel.cs

@@ -0,0 +1,110 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+using SabreTools.Library.Data;
+using SabreTools.Library.DatFiles;
+using SabreTools.Library.Help;
+using SabreTools.Library.Tools;
+
+namespace SabreTools.Library.Help
+{
+    /// <summary>
+    /// Represents an actionable top-level feature
+    /// </summary>
+    public abstract class TopLevel : Feature
+    {
+        public List<string> Inputs = new List<string>();
+
+        /// <summary>
+        /// Process args list based on current feature
+        /// </summary>
+        public virtual bool ProcessArgs(string[] args, Help help)
+        {
+            for (int i = 1; i < args.Length; i++)
+            {
+                // Verify that the current flag is proper for the feature
+                if (!ValidateInput(args[i]))
+                {
+                    Globals.Logger.Error($"Invalid input detected: {args[i]}");
+                    help.OutputIndividualFeature(this.Name);
+                    Globals.Logger.Close();
+                    return false;
+                }
+
+                // Special precautions for files and directories
+                if (File.Exists(args[i]) || Directory.Exists(args[i]))
+                    Inputs.Add(args[i]);
+            }
+
+            return true;
+        }
+
+        /// <summary>
+        /// Process and extract variables based on current feature
+        /// </summary>
+        public virtual void ProcessFeatures(Dictionary<string, Feature> features) { }
+
+        #region Generic Extraction
+
+        /// <summary>
+        /// Get boolean value from nullable feature
+        /// </summary>
+        protected bool GetBoolean(Dictionary<string, Feature> features, string key)
+        {
+            if (!features.ContainsKey(key))
+                return false;
+
+            return true;
+        }
+
+        /// <summary>
+        /// Get int value from nullable feature
+        /// </summary>
+        protected int GetInt32(Dictionary<string, Feature> features, string key)
+        {
+            if (!features.ContainsKey(key))
+                return Int32.MinValue;
+
+            return features[key].GetInt32Value();
+        }
+
+        /// <summary>
+        /// Get long value from nullable feature
+        /// </summary>
+        protected long GetInt64(Dictionary<string, Feature> features, string key)
+        {
+            if (!features.ContainsKey(key))
+                return Int64.MinValue;
+
+            return features[key].GetInt64Value();
+        }
+
+        /// <summary>
+        /// Get list value from nullable feature
+        /// </summary>
+        protected List<string> GetList(Dictionary<string, Feature> features, string key)
+        {
+            if (!features.ContainsKey(key))
+                return new List<string>();
+
+            return features[key].GetListValue() ?? new List<string>();
+        }
+
+        /// <summary>
+        /// Get string value from nullable feature
+        /// </summary>
+        protected string GetString(Dictionary<string, Feature> features, string key)
+        {
+            if (!features.ContainsKey(key))
+                return null;
+
+            return features[key].GetStringValue();
+        }
+
+        #endregion
+    }
+}