Ignore Mac DS_Store (#598)

* Update .gitignore

Navigating to a folder using the "Finder" on Mac generates a .DS_Store file holding metadata about the folder (e.g. thumbnails etc.). These files can pollute your git commits and are annoying.

* Update MovingAverageCalculator.cs

Pull methods and expose accessors on base class for consistency.

.gitignore

@@ -456,4 +456,7 @@ launchSettings.json
 **/keys.bin
 dist/
 data/**
-!data/.gitkeep
+!data/.gitkeep
+
+## Mac specific
+.DS_Store

src/ExchangeSharp/Traders/MovingAverageCalculator.cs

@@ -30,6 +30,9 @@ public abstract class MovingAverageCalculatorBase<T>
         protected T _previousMovingAverage;
         protected T _previousExponentialMovingAverage;
 
+        public int WindowSize => _windowSize;
+
+        public T WeightingMultiplier => _weightingMultiplier;
         /// <summary>
         /// Current moving average
         /// </summary>
@@ -58,6 +61,17 @@ public override string ToString()
         {
             return string.Format("{0}:{1}, {2}:{3}", MovingAverage, Slope, ExponentialMovingAverage, ExponentialSlope);
         }
+
+        /// <summary>
+        /// Gets a value indicating whether enough values have been provided to fill the
+        /// specified window size.  Values returned from NextValue may still be used prior
+        /// to IsMature returning true, however such values are not subject to the intended
+        /// smoothing effect of the moving average's window size.
+        /// </summary>
+        public bool IsMature
+        {
+            get { return _valuesIn == _windowSize; }
+        }
     }
 
     /// <summary>
@@ -126,17 +140,6 @@ public void NextValue(double nextValue)
             }
         }
 
-        /// <summary>
-        /// Gets a value indicating whether enough values have been provided to fill the
-        /// specified window size.  Values returned from NextValue may still be used prior
-        /// to IsMature returning true, however such values are not subject to the intended
-        /// smoothing effect of the moving average's window size.
-        /// </summary>
-        public bool IsMature
-        {
-            get { return _valuesIn == _windowSize; }
-        }
-
         /// <summary>
         /// Clears any accumulated state and resets the calculator to its initial configuration.
         /// Calling this method is the equivalent of creating a new instance.