GH703: Add FileLogger switches to MSBuild Runner

Addresses issue #703

Provides the ability to add FileLogger parameters to the MsBuild command
line.  The various fileloggerparameters (flp) can also be specified.

The parameters that can be created are /fl, /fl[1 thru 9], /flp, and
/flp[1 thru 9]

src/Cake.Common.Tests/Unit/Tools/MSBuild/MSBuildSettingsTests.cs

@@ -126,5 +126,18 @@ public void Should_Be_Empty_By_Default()
                 Assert.Empty(settings.Loggers);
             }
         }
+
+        public sealed class TheFileLoggersProperty
+        {
+            [Fact]
+            public void Should_Be_Empty_By_Default()
+            {
+                // Given
+                var settings = new MSBuildSettings();
+
+                // Then
+                Assert.Empty(settings.FileLoggers);
+            }
+        }
     }
 }