Read fp-info-cache on first start of fp editor

if fp info list is not initialized

pcbnew/footprint_edit_frame.cpp

@@ -861,6 +861,10 @@ void FOOTPRINT_EDIT_FRAME::initLibraryTree()
     FP_LIB_TABLE*   fpTable = Prj().PcbFootprintLibs();
 
     WX_PROGRESS_REPORTER progressReporter( this, _( "Loading Footprint Libraries" ), 2 );
+    if( GFootprintList.GetCount() == 0 )
+    {
+        GFootprintList.ReadCacheFromFile( Prj().GetProjectPath() + "fp-info-cache" );
+    }
     GFootprintList.ReadFootprintFiles( fpTable, NULL, &progressReporter );
     progressReporter.Show( false );