Have parameter types imports use non __init__

When using isort, the order of parametertree/__init__.py imports broke many
of the parameter-types imports.  This commit modifies the import statement to
not use the imports from __init__.py but import the respective classes from the
the non-__init__ modules

pyqtgraph/parametertree/parameterTypes/action.py

@@ -1,4 +1,5 @@
-from .. import ParameterItem, Parameter
+from ..ParameterItem import ParameterItem
+from ..Parameter import Parameter
 from ...Qt import QtWidgets, QtCore
 
 

pyqtgraph/parametertree/parameterTypes/basetypes.py

@@ -1,6 +1,8 @@
 import builtins
 
-from .. import ParameterItem, Parameter
+from ..ParameterItem import ParameterItem
+from ..Parameter import Parameter
+
 from ... import functions as fn
 from ...Qt import QtWidgets, QtCore, QtGui
 from ... import icons

pyqtgraph/parametertree/parameterTypes/calendar.py

@@ -1,5 +1,5 @@
 from ...Qt import QtWidgets, QtCore
-from .. import Parameter
+from ..Parameter import Parameter
 from .basetypes import WidgetParameterItem
 
 

pyqtgraph/parametertree/parameterTypes/checklist.py

@@ -2,7 +2,7 @@ from . import BoolParameterItem, SimpleParameter
 from .basetypes import GroupParameterItem, GroupParameter, WidgetParameterItem
 from .list import ListParameter
 from .slider import Emitter
-from .. import ParameterItem
+from ..ParameterItem import ParameterItem
 from ... import functions as fn
 from ...Qt import QtWidgets
 

pyqtgraph/parametertree/parameterTypes/file.py

@@ -2,7 +2,7 @@ import os
 import re
 
 from .str import StrParameterItem
-from .. import Parameter
+from ..Parameter import Parameter
 from ...Qt import QtWidgets, QtGui, QtCore
 
 

pyqtgraph/parametertree/parameterTypes/font.py

@@ -1,5 +1,5 @@
 from .basetypes import WidgetParameterItem
-from .. import Parameter
+from ..Parameter import Parameter
 from ...Qt import QtWidgets, QtGui
 
 

pyqtgraph/parametertree/parameterTypes/list.py

@@ -2,7 +2,7 @@ import warnings
 from collections import OrderedDict
 
 from .basetypes import WidgetParameterItem
-from .. import Parameter
+from ..Parameter import Parameter
 from ...Qt import QtWidgets
 from ... import functions as fn
 

pyqtgraph/parametertree/parameterTypes/pen.py

@@ -1,5 +1,5 @@
 from .basetypes import WidgetParameterItem
-from .. import Parameter
+from ..Parameter import Parameter
 from ... import functions as fn
 from ...Qt import QtWidgets, QtGui, QtCore
 from ...widgets.PenSelectorDialog import PenSelectorDialog

pyqtgraph/parametertree/parameterTypes/progress.py

@@ -1,5 +1,5 @@
 from ...Qt import QtWidgets
-from .. import Parameter
+from ..Parameter import Parameter
 from .basetypes import WidgetParameterItem
 
 

pyqtgraph/parametertree/parameterTypes/slider.py

@@ -1,7 +1,7 @@
 import numpy as np
 
 from .basetypes import WidgetParameterItem, Emitter
-from .. import Parameter
+from ..Parameter import Parameter
 from ...Qt import QtCore, QtWidgets
 
 class SliderParameterItem(WidgetParameterItem):

pyqtgraph/parametertree/parameterTypes/text.py

@@ -1,5 +1,5 @@
 from .basetypes import WidgetParameterItem
-from .. import Parameter
+from ..Parameter import Parameter
 from ...Qt import QtWidgets, QtCore