Fix issue with spaces after comma and or filters

Combined filters separated with comma and a space resulted in an error. 
Example: 
Title==D, (Title|LikeCount)==3
Caused the error: "(Title not found"

Extended regex to allow whitespaces after the comma as documented.

Sieve/Models/SieveModel.cs

@@ -13,7 +13,7 @@ namespace Sieve.Models
         where TFilterTerm : IFilterTerm, new()
         where TSortTerm : ISortTerm, new()
     {
-        private const string EscapedCommaPattern = @"(?<!($|[^\\])(\\\\)*?\\),";
+        private const string EscapedCommaPattern = @"(?<!($|[^\\])(\\\\)*?\\),\s*";
 
         [DataMember]
         public string Filters { get; set; }

SieveUnitTests/General.cs

@@ -352,6 +352,23 @@ namespace SieveUnitTests
             Assert.AreEqual(3, entry.Id);
         }
 
+        [TestMethod]
+        public void CombinedAndOrWithSpaceFilteringWorks()
+        {
+            var model = new SieveModel()
+            {
+                Filters = "Title==D, (Title|LikeCount)==3",
+            };
+
+            var result = _processor.Apply(model, _posts);
+            var entry = result.FirstOrDefault();
+            var resultCount = result.Count();
+
+            Assert.IsNotNull(entry);
+            Assert.AreEqual(1, resultCount);
+            Assert.AreEqual(3, entry.Id);
+        }
+
         [TestMethod]
         public void OrValueFilteringWorks()
         {