[update] make PYQTGRAPH mandatory for PyLoT (stop maintaining unused stuff)!

PyLoT.py

@@ -48,11 +48,7 @@ from obspy.core.util import AttribDict
 
 from pylot.core.util.obspyDMT_interface import check_obspydmt_structure
 
-try:
 import pyqtgraph as pg
-except Exception as e:
-    print('PyLoT: Could not import pyqtgraph. {}'.format(e))
-    pg = None
 
 try:
     from matplotlib.backends.backend_qt4agg import FigureCanvas

pylot/core/util/utils.py

@@ -22,12 +22,7 @@ from pylot.styles import style_settings
 from scipy.interpolate import splrep, splev
 from PySide import QtCore, QtGui
 
-try:
 import pyqtgraph as pg
-except Exception as e:
-    print('PyLoT: Could not import pyqtgraph. {}'.format(e))
-    pg = None
-
 
 def _pickle_method(m):
     if m.im_self is None:

pylot/core/util/widgets.py

@@ -4404,7 +4404,7 @@ class GraphicsTab(PropTab):
         super(GraphicsTab, self).__init__(parent)
         self.pylot_mainwindow = parent._pylot_mainwindow
         self.init_layout()
-        self.add_pg_cb()
+        #self.add_pg_cb()
         self.add_nth_sample()
         self.add_style_settings()
         self.setLayout(self.main_layout)
@@ -4441,12 +4441,7 @@ class GraphicsTab(PropTab):
         self.main_layout.addWidget(self.spinbox_nth_sample, 1, 1)
 
     def add_pg_cb(self):
-        try:
-            import pyqtgraph as pg
         pg = True
-        except:
-            pg = False
-
         text = {True: 'Use pyqtgraphic library for plotting',
                 False: 'Cannot use library: pyqtgraphic not found on system'}
         label = QLabel('PyQt graphic')