Fix #540: Dot character should not be an error char in C#

RSyntaxTextArea/src/main/java/org/fife/ui/rsyntaxtextarea/modes/CSharpTokenMaker.flex

@@ -306,7 +306,7 @@ OperatorOrPunctuator					= ({OOPHelper1}|{OOPHelper2}|{OOPHelper3}|{OOPHelper4}|
 /* NOTE:  We distinguish between operators and separators (punctuators), but */
 /* the C# spec doesn't, so the stuff below isn't in the spec.                */
 Separator								= ([\{\}\[\]\(\)])
-Separator2							= ([,;])
+Separator2							= ([,;.])
 
 /* C.1.10 - Pre-processing Directives. */
 /* NOTE:  We don't do ALL of the PP stuff here as it's unnecessary  */

RSyntaxTextArea/src/test/java/org/fife/ui/rsyntaxtextarea/modes/CSharpTokenMakerTest.java

@@ -1,4 +1,4 @@
-/*
+	/*
  * 06/05/2016
  *
  * This library is distributed under a modified BSD license.  See the included
@@ -193,6 +193,17 @@ void testHexLiterals() {
 	}
 
 
+	@Test
+	void testIdentifiers() {
+		assertAllTokensOfType(TokenTypes.IDENTIFIER,
+			"Foobar",
+			",",
+			".",
+			";"
+		);
+	}
+
+
 	@Test
 	void testKeywords() {
 

RSyntaxTextAreaDemo/src/main/java/org/fife/ui/rsyntaxtextarea/demo/DemoRootPane.java

@@ -102,6 +102,7 @@ private JMenuBar createMenuBar() {
 		addSyntaxItem("6502 Assembler", "Assembler6502.txt", SYNTAX_STYLE_ASSEMBLER_6502, bg, menu);
 		addSyntaxItem("ActionScript", "ActionScriptExample.txt", SYNTAX_STYLE_ACTIONSCRIPT, bg, menu);
 		addSyntaxItem("C",    "CExample.txt", SYNTAX_STYLE_C, bg, menu);
+		addSyntaxItem("C#",    "CSharpExample.txt", SYNTAX_STYLE_CSHARP, bg, menu);
 		addSyntaxItem("CSS",  "CssExample.txt", SYNTAX_STYLE_CSS, bg, menu);
 		addSyntaxItem("Dockerfile", "DockerfileExample.txt", SYNTAX_STYLE_DOCKERFILE, bg, menu);
 		addSyntaxItem("Go", "GoExample.txt", SYNTAX_STYLE_GO, bg, menu);

RSyntaxTextAreaDemo/src/main/resources/org/fife/ui/rsyntaxtextarea/demo/CSharpExample.txt

@@ -0,0 +1,13 @@
+using System;
+
+namespace HelloWorld
+{
+  class Program
+  {
+    // Program entry point
+    static void Main(string[] args)
+    {
+      Console.WriteLine("Hello World!");
+    }
+  }
+}