Moved the CppHoverHandler to the CppEditor plugin

It used to be in CppTools, but since the hover handler only makes sense
in the context of the C++ editor, this is a better place.

src/plugins/cpptools/cpptools.pro

@@ -25,14 +25,11 @@ SOURCES += cppquickopenfilter.cpp \
 # Input
 SOURCES += cpptoolsplugin.cpp \
     cppmodelmanager.cpp \
-    cppcodecompletion.cpp \
-    cpphoverhandler.cpp
+    cppcodecompletion.cpp
 HEADERS += cpptoolsplugin.h \
     cppmodelmanager.h \
     cppcodecompletion.h \
-    cpphoverhandler.h \
     cppmodelmanagerinterface.h \
     cpptoolseditorsupport.h \
     cpptoolsconstants.h
-RESOURCES += cpptools.qrc
 FORMS += completionsettingspage.ui