Improvements in textedit and hotkey manager

* Set textedit's cursor position to the end of text in some situations
* Send hotkey messages to the current channel instead of default channel
* Allow to overwrite sprites using otml and pngs

src/framework/ui/uitextedit.cpp

@@ -327,6 +327,9 @@ void UITextEdit::update(bool focusCursor)
 
 void UITextEdit::setCursorPos(int pos)
 {
+    if(pos < 0)
+        pos = m_text.length();
+
     if(pos != m_cursorPos) {
         if(pos < 0)
             m_cursorPos = 0;