Disregard case in Apple box names + initial unit test (#187)

Author: teekay

src/TaglibSharp.Tests/FileFormats/M4aFormatTest.cs

@@ -21,6 +21,7 @@ public Mpeg4TestFile (string path) : base (path)
 		}
 
 		static readonly string sample_file = TestPath.Samples + "sample.m4a";
+		static readonly string sample_file_rg = TestPath.Samples + "sample_replaygain.m4a";
 		static readonly string tmp_file = TestPath.Samples + "tmpwrite.m4a";
 		static readonly string aac_broken_tags = TestPath.Samples + "bgo_658920.m4a";
 		TagLib.File file;
@@ -93,6 +94,13 @@ public void ReadTags ()
 			Assert.AreEqual (1234, file.Tag.Year);
 		}
 
+		[Test]
+		public void ReadReplayGain()
+		{
+			var fileWithRg = TagLib.File.Create (sample_file_rg);
+			Assert.AreEqual(-1.43, fileWithRg.Tag.ReplayGainTrackGain, 0.01);
+		}
+
 		[Test]
 		public void WriteStandardTags ()
 		{

src/TaglibSharp.Tests/samples/sample_replaygain.m4a

@@ -471,7 +471,7 @@ AppleDataBox GetDashAtoms (string meanstring, string namestring)
 
 				if (mean_box == null || name_box == null ||
 					mean_box.Text != meanstring ||
-					name_box.Text != namestring) {
+					!name_box.Text.Equals (namestring, StringComparison.OrdinalIgnoreCase)) {
 					continue;
 				} else {
 					return (AppleDataBox)box.GetChild (BoxType.Data);