Refactor all math into a new kimath library

* Split up the thirdparty code into the thirdparty folder (#3637)
* Create a new kimath static library containing all the math functions

This is part of cleaning the build system for #1906.

common/base_screen.cpp

@@ -29,13 +29,15 @@
  * @brief BASE_SCREEN object implementation.
  */
 
-#include <fctsys.h>
-#include <macros.h>
-#include <common.h>
-#include <base_struct.h>
+
 #include <base_screen.h>
-#include <id.h>
+#include <base_struct.h>
 #include <base_units.h>
+#include <common.h>
+#include <fctsys.h>
+#include <id.h>
+#include <math/util.h>      // for KiROUND
+#include <macros.h>
 #include <trace_helpers.h>