Code cleanup: remove useless wx/wx.h include inside a few files.

in most of files, including wx.h is not necessary, when only 2 or 3 wx files must be included.
Moreover, on windows, including wx.h sometimes create compil warnings about
shadowed vars defined in some specific windows headers.

common/common.cpp

@@ -23,7 +23,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-#include <fctsys.h>
 #include <eda_base_frame.h>
 #include <project.h>
 #include <common.h>
@@ -39,8 +38,6 @@
 #include <boost/uuid/uuid_io.hpp>
 #include <boost/functional/hash.hpp>
 
-using KIGFX::COLOR4D;
-
 
 // Create only once, as seeding is *very* expensive
 static boost::uuids::random_generator randomGenerator;