#10 aedTextBox should clear selection when it loses focus

[bak]

otherwise, there can be multiple selections if they have more than one textbox, which looks strange. The simplest fix is to add a wm_lostfocus to the class:

virtual int wm_lostfocus()
{
setSelection(0, 0);
m_Selecting = false;
setRenderState(true);

return 0;

}

As a side note, I think this is the best-looking SDL GUI around, and other than it missing a few controls and these occasional bugs, it's very nice. Good work, I hope development picks up again, however doubtful.