Remove unused extension methods

When I introduced the `SqlDataReader` extension methods in #dde0ade, I added a few that _might_ be needed—and, indeed, might _still_ be needed in the future—but aren't needed _yet_. Since this is a private library intended only to support the `SqlTopicRepository`, there's no real benefit to maintaining private methods that aren't being used. And, in fact, given _how_ they're being used, it's unlikely (but not impossible) that we'll need them given the current approach to the SQL schema. (I.e., since most attributes are stored as strings in both the database as well as the topic library, there isn't a need to use e.g. `GetBoolean()`, unless we add a new metadata column that's a `BIT`.)

Author: JeremyCaney

OnTopic.Data.Sql/SqlDataReaderExtensions.cs

@@ -19,7 +19,6 @@ namespace OnTopic.Data.Sql {
   /// </summary>
   internal static class SqlDataReaderExtensions {
 
-
     /*==========================================================================================================================
     | DELEGATE: TRY PARSE
     \-------------------------------------------------------------------------------------------------------------------------*/
@@ -47,17 +46,6 @@ internal static int GetInteger(this SqlDataReader reader, string columnName) =>
     internal static string GetString(this SqlDataReader reader, string columnName) =>
       GetValue<string>(reader, columnName, (string source, out string value) => { value = source; return true; }, String.Empty);
 
-    /*==========================================================================================================================
-    | METHOD: GET DATE/TIME
-    \-------------------------------------------------------------------------------------------------------------------------*/
-    /// <summary>
-    ///   Retrieves a <see cref="DateTime"/> value by column name.
-    /// </summary>
-    /// <param name="reader">The <see cref="SqlDataReader"/> object.</param>
-    /// <param name="columnName">The name of the column to retrieve the value from.</param>
-    internal static DateTime GetDateTime(this SqlDataReader reader, string columnName) =>
-      GetValue<DateTime>(reader, columnName, DateTime.TryParse, DateTime.MinValue);
-
     /*==========================================================================================================================
     | METHOD: GET VERSION
     \-------------------------------------------------------------------------------------------------------------------------*/
@@ -68,17 +56,6 @@ internal static DateTime GetDateTime(this SqlDataReader reader, string columnNam
     internal static DateTime GetVersion(this SqlDataReader reader) =>
       reader.GetDateTime(reader.GetOrdinal("Version"));
 
-    /*==========================================================================================================================
-    | METHOD: GET BOOLEAN
-    \-------------------------------------------------------------------------------------------------------------------------*/
-    /// <summary>
-    ///   Retrieves a <see cref="Boolean"/> value by column name.
-    /// </summary>
-    /// <param name="reader">The <see cref="SqlDataReader"/> object.</param>
-    /// <param name="columnName">The name of the column to retrieve the value from.</param>
-    internal static bool GetBoolean(this SqlDataReader reader, string columnName) =>
-      GetValue<bool>(reader, columnName, Boolean.TryParse, false);
-
     /*==========================================================================================================================
     | METHOD: GET VALUE
     \-------------------------------------------------------------------------------------------------------------------------*/