Improve comment support in Xojo lexer (#1229)

This commit:

- adds single quote and 'rem' style comments;
- fixes parsing with multiple Note sections;
- adds `.xojo_image`, `.rbbas`, `.rbfrm`, `.rbmnu`, `.rbres`, `.rbtbar` 
  file extensions (these are old REALbasic file names); and
- updates demo and test files with added comment styles.

lib/rouge/demos/xojo

@@ -1,7 +1,8 @@
 Dim f As FolderItem
 f = GetOpenFolderItem(FileTypes1.jpeg) // defined in the File Type Set editor
+rem - we should check for nil!
 If not f.Exists Then
-  Beep
+  Beep 'Just for fun
   MsgBox("The file " + f.NativePath + "doesn't ""exist.""")
 Else // document exists
   ImageWell1.image=Picture.Open(f)

lib/rouge/lexers/xojo.rb

@@ -8,7 +8,7 @@ class Xojo < RegexLexer
       desc "Xojo"
       tag 'xojo'
       aliases 'realbasic'
-      filenames '*.xojo_code', '*.xojo_window', '*.xojo_toolbar', '*.xojo_menu'
+      filenames '*.xojo_code', '*.xojo_window', '*.xojo_toolbar', '*.xojo_menu', '*.xojo_image', '*.rbbas', '*.rbfrm', '*.rbmnu', '*.rbres', '*.rbtbar'
 
       keywords = %w(
           addhandler aggregates array asc assigns attributes begin break
@@ -30,15 +30,15 @@ class Xojo < RegexLexer
         )
 
       operator_words = %w(
-          addressof and as in is isa mod not or xor
+          addressof weakaddressof and as in is isa mod not or xor
         )
 
       state :root do
         rule %r/\s+/, Text::Whitespace
 
         rule %r/rem\b.*?$/i, Comment::Single
-        rule %r(//.*$), Comment::Single
-        rule %r/\#tag Note.*\#tag EndNote/m, Comment::Preproc
+        rule %r([//'].*$), Comment::Single
+        rule %r/\#tag Note.*?\#tag EndNote/mi, Comment::Preproc
         rule %r/\s*[#].*$/x, Comment::Preproc
 
         rule %r/".*?"/, Literal::String::Double

spec/visual/samples/xojo

@@ -34,6 +34,8 @@ End
 		  dim y as double=.1 //also allowed
 		  rem This is an old style comment (throw back to Basic)
 		  dim escaped_quotes as string="this is an ""escaped"" string" //would compile as 'this is an "escaped" string'
+		  'this is a single quote comment
+		  msgbox "ok" 'this should be a comment too!
 		End Sub
 	#tag EndEvent
 
@@ -227,6 +229,13 @@ End
 		End Sub
 	#tag EndEvent
 #tag EndEvents
+
+#tag Note, Name = More Notes
+		This another note to make sure we're not grabbing too much/multiple 
+		notes.
+
+#tag EndNote
+
 #tag ViewBehavior
 	#tag ViewProperty
 		Name="BackButtonTitle"