Added Utils class.

utils/Utils.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace GeometriCS
+{
+    /// <summary>
+    /// Common utilities throughout the library.
+    /// </summary>
+    internal static class Utils
+    {
+        /// <summary>
+        /// Default precision for double equality comparison.
+        /// </summary>
+        private const double DOUBLEPRECISION = 1E-5;
+
+        /// <summary>
+        /// Tests whether the difference between two doubles is within a given limit.
+        /// </summary>
+        /// <param name="a">First value to test.</param>
+        /// <param name="b">Second value to test.</param>
+        /// <param name="prec">Maximum allowed difference.</param>
+        /// <returns>Do the values almost equal each other.</returns>
+        public static bool DoubleEquals(double a, double b, double prec = DOUBLEPRECISION) => Math.Abs(a - b) <= prec;  
+    }
+}