Fixed more Haxe 3 regressions (thanks to cambiata)

Commit tested with v3-00-rc1 branch. Fixes suggested by cambiata (https://github.com/cambiata)
Reference ticket : https://github.com/njuneau/Harfang/issues/6
Merge branch '0.4' into 0.5
Additionnal fixes for 0.3 regressions

Added additionnal fixes suggested in https://github.com/njuneau/Harfang/issues/6