In progress: [ Issue 87 ] Protobuf editor does not recognize "import
public"

Added "import public" to the language grammar.
diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
index f1e61b7..81c3731 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
@@ -28,8 +28,14 @@
   'package' name=QualifiedName ';';
 
 Import: 
+  RegularImport | PublicImport;
+
+RegularImport:
   'import' importURI=STRING ';';
 
+PublicImport:
+  'import' 'public' importURI=STRING ';';
+
 QualifiedName:
   '.'? Name ('.' Name)*;