https://bugs.kde.org/show_bug.cgi?id=449622#c5 fix for displaced pins, ports,...

https://bugs.kde.org/show_bug.cgi?id=449622#c5 fix for displaced pins, ports, and their associated floating texts

umbrello/umlwidgets/umlwidget.cpp followup to commit d8fe02e4
- In function loadFromXMI :
  - Initialize fixedX to just nX.
  - Initialize fixedY to just nY.
  - Local bool usesRelativeCoords indicates whther this widget's
    coordinates are relative to its parentItem().
  - Apply umlScene()->fixX() to fixedX and apply umlScene()->fixY() to
    fixedY only if usesRelativeCoords is false.
  - Call umlScene()->updateCanvasSizeEstimate() only if
    usesRelativeCoords is false.

umbrello/umlwidgets/pinportbase.cpp
- In function loadFromXMI, on loading optional child floatingtext move
  call to m_pName->setParentItem(this) to before m_pName->loadFromXMI().
  Reason: UMLWidget::loadFromXMI needs to evaluate whether the widget
  coordinates are relative to a parent UMLWidget (see above).

CCBUG: 449622