Added Color Picker plugin
Point, Flicker and Pulse light animation should now look almost exactly as seen in GZDoom.
Fixed a bug when editing thing properties in Visual mode didn't update visual thing.
Fixed incorrect doom-style walls shading when sector has "lightcolor" property set.
Fixed "Index was outside the bounds of the array in CalculateNormalsAndShading()" error.
GZDoomBuilder will now show error message prior to failing.
Added two new type handlers that can be used in UDMF ('Thing Type' and 'Thing Class')
Polished the browse icons and browse buttons.
Added more events for plugins to intercept.
