Fixed Exception dialog disapearing after a view second when exception occurs during app startup.
Problem was caused by splashscreen timeout, wx closing averything else if there is no more main frame.
Changes:
- no more timeout for splashscreen
- use wx.App OnInit method to give first operation to mainloop, object are then now created in mainloop
- main loop is then created _before_ showing splash screen
- no more wxyield or wx processevent tricks needed to display splash screen
- exception handler not blocking anymore on dialog (callafter)
- because of mainloop being there before everything, exit must be called explicitely if exception caught during startup -> exit parameter in handle_exception + try/except around startup calls

UNTESTED ON WINDOWS

{
    "url":"ws://127.0.0.1:8888",
    "realm":"Automation",
    "ID":"wamptest",
    "password":"1234567890",
    "key":"ABCDEFGHIJ"
}