Clean exported headers of the CppTools plugin.

Change-Id: I0144ac33e88980c431c54a6d69bbde28da4b1967
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/cpptools/symbolfinder.h

@@ -33,13 +33,20 @@
 
 #include "cpptools_global.h"
 
-#include <cplusplus/CppDocument.h>
-
 #include <QHash>
 #include <QStringList>
 #include <QMultiMap>
 #include <QSet>
 
+namespace CPlusPlus {
+class Class;
+class Declaration;
+class Function;
+class LookupContext;
+class Snapshot;
+class Symbol;
+}
+
 namespace CppTools {
 
 class CPPTOOLS_EXPORT SymbolFinder