This provides an improved user experience, allowing cursor movement
directly from the keyboard.

- Fixes an off-by-one error when navigating by rows, caused by treating
  the table header as a row. The table header now has the header
  accessibility role.
- Fixes a bug where reordering table columns would cause the table to
  become inaccessible.
- Fixes a bug where the screen reader would try to navigate hidden table
  columns.
- Fixes an issue where moving the VoiceOver cursor to a partially hidden
  cell would cause the focus to move to the table itself, rather than to
  the cell.

This change avoids a situation where a standalone plugin's Audio/Midi
settings window could appear in a wrong position.

Using this new function a previous bug is avoided where transforms
were applied differently to drawable paths and text elements.

Before this commit it was possible for the plugin to transfer control
to its internal MessageThread and call
IComponentHandler::restartComponent() from it.

On Windows, when opening a plugin editor, destroying the plugin
instance, and then creating a new instance and opening its editor, the
plugin would crash because the VBlankDispatcher singleton could not be
recreated.

Previously opening a PopupMenu and then clicking somewhere outside
the application would cause the mouse button representation to be
stuck in a down state.

In 6f3fb5a29f windowBorder member of
LinuxComponentPeer was changed to mean the logical size of the border
that is independent of the current scale factor. This was done to fix a
bug and make it consistent with the bounds member, which is also
independent from the scale factor.

This change wasn't taken into account in XWindowSystem::setBounds()
causing a positioning bug.

An animated drag operation will now stop if the user interacts with
the content area again before the animation is finished. It is also
stopped if the user interacts with the scrollbars.

Previously, positioning such an item would hang while trying to find an
appropriate position for the item, because no position in the grid was
suitable, and implicit cells in the layout direction would be added
until a viable position was found.

We now ensure that there are enough cells in the cross direction to hold
each of the auto-placement items before trying to position those items.