fix : some user cannot use certain Freeseer tools that make use of setplaceholdertext(). Because their version of PyQt4 is too old.
 if hasattr(QtGui.QLineEdit(), 'setPlaceholderText'):
Merge pull request #296 from hosi-mo/fix/pyqt4.7.3_2

fix: Check for existence of setPlaceholderText was checking for exact version

- Fixed the check for Qt method setPlaceholderText() was checking if 
  the user had exactly python version 4.7.3, instead we are now
  checking the property exists.