(more noticeable in eeschema)

change EXCHG macro to equivalent inline functions
(better code compatibility with some compilers)

Added: Zones unfill in polygon mode

pcbnew: added oblong thermal relief for oblong pads (from a contribution) . added contributor to kicad list

solved a very subtle bug in polygon_test_point_inside.cpp. Sometimes a point outside a polygon was seen inside the polygon

Solved bug in zone filling by polygons: a forgotten conversion to double. using int in calculations creates sometimes overflows and erroneous filling
Add patch to handle oblong pads

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solved pcbnew: minor bug when only one copper layer selected: zone properties layer list displayed component layer instead of copper layer