Fixed QxtLineEdit to compile with Qt < 4.5.
Fixed QxtLineEdit to compile with Qt < 4.5.

mmitkevich/libqxt,mmitkevich/libqxt,mmitkevich/libqxt,hrobeers/qxtweb-qt5,hrobeers/qxtweb-qt5,hrobeers/qxtweb-qt5,hrobeers/qxtweb-qt5,hrobeers/qxtweb-qt5,mmitkevich/libqxt