Bug 467023 - Minor updates to the DSF Programming Intro

- Add a note about turning pre-processor off so edits made as part of
  the tutorial are not overwritten
- Add missing ConfinedToDsfExecutor for Exercise 4
- Fix typo

Change-Id: I790fc2e3f640510a665a9a29a04f20502af7c710
Signed-off-by: Jonah Graham <jonah@kichwacoders.com>

doc/org.eclipse.cdt.doc.isv/guide/dsf/intro/dsf_programming_intro.html

@@ -159,6 +159,8 @@ exercises preprocessor.</li>
 sources generated by the preprocessor.</li>
     <li>Build the plugin again to compile the generated sources.</li>
   </ol>
+  <li>Turn off the preprocessor so that edits made as part of the tutorial are not overwritten. Open Project
+Properties, choose Builder and uncheck "PreProcessor".</li>
   <li>Launch the examples</li>
   <ol style="list-style-type: lower-alpha;">
     <li>Examples in data <span style="font-style: italic;">org.eclipse.cdt.examples.dsf.requestmonitor</span>

dsf/org.eclipse.cdt.examples.dsf/src_preprocess/org/eclipse/cdt/examples/dsf/dataviewer/DataGeneratorWithExecutor.java

@@ -60,7 +60,7 @@ public class DataGeneratorWithExecutor implements IDataGenerator {
     // Request objects are used to serialize the interface calls into objects
     // which can then be pushed into a queue.
     //#ifdef exercises
-    // TODO Ecercise 4 - Add an annotationindicating allowed concurrency access
+    // TODO Exercise 4 - Add an annotationindicating allowed concurrency access
     // Hint: Request and its subclasses have all their fields declared as final.
     //#else
 //#    @Immutable
@@ -305,7 +305,13 @@ public class DataGeneratorWithExecutor implements IDataGenerator {
             }, 
             PROCESSING_DELAY, TimeUnit.MILLISECONDS);        
     }
-    
+
+    //#ifdef exercises
+    // TODO Exercise 4 - Add an annotation (ThreadSafe/ConfinedToDsfExecutor)
+    // indicating allowed thread access to this class/method/member
+    //#else
+//#    @ConfinedToDsfExecutor("fExecutor")
+    //#endif
     private void doServiceQueue() {
         //#ifdef exercises
         // TODO Exercise 3 - Add logic to discard cancelled requests from queue.