tuned imports -- accommodate scala-2.13.0-RC3;

--- a/src/Tools/VSCode/src/channel.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/channel.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -8,6 +8,7 @@
 
 
 import isabelle._
+import isabelle.vscode.Protocol
 
 import java.io.{InputStream, OutputStream, FileOutputStream, ByteArrayOutputStream, File => JFile}
 

--- a/src/Tools/VSCode/src/document_model.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/document_model.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -8,6 +8,7 @@
 
 
 import isabelle._
+import isabelle.vscode.{Protocol, Server}
 
 import java.io.{File => JFile}
 

--- a/src/Tools/VSCode/src/dynamic_output.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/dynamic_output.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -8,6 +8,7 @@
 
 
 import isabelle._
+import isabelle.vscode.{Protocol, Server}
 
 
 object Dynamic_Output

--- a/src/Tools/VSCode/src/preview_panel.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/preview_panel.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -8,6 +8,7 @@
 
 
 import isabelle._
+import isabelle.vscode.Protocol
 
 import java.io.{File => JFile}
 

--- a/src/Tools/VSCode/src/protocol.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/protocol.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -9,6 +9,7 @@
 
 
 import isabelle._
+import isabelle.vscode.Server
 
 import java.io.{File => JFile}
 

--- a/src/Tools/VSCode/src/server.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/server.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -12,6 +12,7 @@
 
 
 import isabelle._
+import isabelle.vscode.{Protocol, Server}
 
 import java.io.{PrintStream, OutputStream, File => JFile}
 

--- a/src/Tools/VSCode/src/state_panel.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/state_panel.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -8,6 +8,7 @@
 
 
 import isabelle._
+import isabelle.vscode.{Protocol, Server}
 
 
 object State_Panel

--- a/src/Tools/VSCode/src/vscode_rendering.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/vscode_rendering.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -9,6 +9,7 @@
 
 
 import isabelle._
+import isabelle.vscode.Protocol
 
 import java.io.{File => JFile}
 

--- a/src/Tools/VSCode/src/vscode_resources.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/vscode_resources.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -8,6 +8,7 @@
 
 
 import isabelle._
+import isabelle.vscode.{Protocol, Server}
 
 import java.io.{File => JFile}
 

--- a/src/Tools/VSCode/src/vscode_spell_checker.scala	Sat Jun 01 21:43:03 2019 +0200
+++ b/src/Tools/VSCode/src/vscode_spell_checker.scala	Sat Jun 01 21:43:41 2019 +0200
@@ -8,6 +8,7 @@
 
 
 import isabelle._
+import isabelle.vscode.Protocol
 
 
 object VSCode_Spell_Checker