In the C++ standard, this function is only defined for floating point
types, and integers cannot be implicitly converted. Using explicit
conversions avoids a GCC specific extension to the standard library.
include/vector2d.h: Removed old version
include/math/math_util.h: rescale() for VECTOR2
include/math/vector2d.h: New version of VECTOR2
include/math/box2.h: New version of BOX2
common/drawframe.cpp: Refactorization of code, so it is compatible with new classes
include/plot_common.h, pcbnew/basepcbframe.cpp: Changed header inclusion path
CMakeLists.txt: Added definition to turn on WX_COMPATIBILITY for replacement classes