pcbnew: corner-smoothed zone fills over keepout

[Chris Pavlina]

The zone-fill algorithm does not properly mind keepouts for zones set with a corner smoothing. This even appears to be 'sticky' - changing the zone back to non-smoothed and refilling does not fix.

1. Create a zone with default settings + 1mm fillet, no net.
2. Create a keepout ("No copper pour", obviously) with a sharp corner intersecting the zone.
3. Refill.

https://misc.c4757p.com/kicad_bad_fill.png

Example PCB file attached.

Application: pcbnew
Version: (2016-02-01 BZR 6532, Git a15df25)-product debug build
wxWidgets: Version 3.0.2 (debug,wchar_t,compiler with C++ ABI 1002,GCC 4.2.1,wx containers,compatible with 2.8)
Platform: Linux 4.3.3-3-ARCH x86_64, 64 bit, Little endian, wxGTK
Boost version: 1.60.0
         USE_WX_GRAPHICS_CONTEXT=OFF
         USE_WX_OVERLAY=OFF
         KICAD_SCRIPTING=ON
         KICAD_SCRIPTING_MODULES=ON
         KICAD_SCRIPTING_WXPYTHON=ON
         USE_FP_LIB_TABLE=HARD_CODED_ON
         BUILD_GITHUB_PLUGIN=ON

Marking Confirmed as I'm reporting this for someone else, we've both seen the behavior.