pyqtgraph < 0.10 fail to run (#13)

src/rqt_plot/data_plot/pyqtgraph_data_plot.py

@@ -43,7 +43,14 @@
         def parse_version(s):
             return [int(x) for x in re.sub(r'(\.0+)*$', '', s).split('.')]
 
-    from pyqtgraph import __version__ as pyqtgraph_version
+    try:
+        from pyqtgraph import __version__ as pyqtgraph_version
+    except RuntimeError:
+        # pyqtgraph < 1.0 using Qt4 failing on 16.04 because kinetic uses Qt5.
+        # This raises RuntimeError('the PyQt4.QtCore and PyQt5.QtCore modules both wrap the QObject class')
+        import pkg_resources
+        pyqtgraph_version = pkg_resources.get_distribution("pyqtgraph").version
+
     if parse_version(pyqtgraph_version) < parse_version('0.10.0'):
         raise ImportError('A newer PyQtGraph version is required (at least 0.10 for Qt 5)')