We should set this to some decent default value that doesn't
look wrong. Note that the width and height definition in
TextArea could cause conflicts when used in layouts.

Change-Id: I815ff96c02f9a9a76c07d57181f3a24291c83c52
Reviewed-by: Jan Arve Sæther <jan-arve.saether@digia.com>
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>