fix splash loading with wx3.0

Previously only gray square was shown. Apparently to show splash screen several calls of wx.Yield() are necessary.
Unfortunately splash.IsShowOnScreen() returns always 1 regardless of whether splash is on the screen or not.
this fix is a dirty hack. It just process all events after splash is created during 0.3 seconds.

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema" URI_location="WAMP://127.0.0.1:8888#Automation#2534667845">
  <TargetType/>
</BeremizRoot>