Drop usage of future and past module

FC Windows distribution doesn't have these modules

constraint.py

@@ -1,4 +1,3 @@
-from future.utils import with_metaclass
 from collections import namedtuple
 import FreeCAD, FreeCADGui
 import asm3
@@ -310,7 +309,8 @@ def cstrName(obj):
     return '{}<{}>'.format(objName(obj),Constraint.getTypeName(obj))
 
 
-class Base(with_metaclass(Constraint,object)):
+class Base(object):
+    __metaclass__ = Constraint
     _id = -1
     _entityDef = ()
     _workplane = False

gui.py

@@ -1,4 +1,3 @@
-from future.utils import with_metaclass
 from collections import OrderedDict
 import FreeCAD, FreeCADGui
 import asm3
@@ -101,7 +100,8 @@ class AsmCmdManager(ProxyType):
     def onClearSelection(cls):
         pass
 
-class AsmCmdBase(with_metaclass(AsmCmdManager,object)):
+class AsmCmdBase(object):
+    __metaclass__ = AsmCmdManager
     _id = -1
     _active = None
     _toolbarName = 'Assembly3'

proxy.py

@@ -1,4 +1,3 @@
-import past.builtins as pb
 from collections import namedtuple
 from asm3.utils import proxylogger as logger, objName
 
@@ -60,7 +59,7 @@ class ProxyType(type):
 
     @classmethod
     def getType(mcs,tp):
-        if isinstance(tp,pb.basestring):
+        if isinstance(tp,basestring):
             return mcs.getInfo().TypeNameMap[tp]
         if not isinstance(tp,int):
             tp = mcs.getTypeID(tp)

sys_slvs.py

@@ -1,9 +1,9 @@
-from future.utils import with_metaclass
 from asm3.system import System, SystemBase, SystemExtension
 from asm3.utils import syslogger as logger, objName
 import asm3.py_slvs.slvs as slvs
 
-class SystemSlvs(with_metaclass(System,SystemBase)):
+class SystemSlvs(SystemBase):
+    __metaclass__ = System
     _id = 1
 
     def __init__(self,obj):

sys_sympy.py

@@ -1,5 +1,4 @@
 from collections import namedtuple
-from future.utils import with_metaclass, iteritems
 import pprint
 from asm3.proxy import ProxyType, PropertyInfo
 from asm3.system import System, SystemBase, SystemExtension
@@ -25,7 +24,8 @@ def _makeProp(name,doc='',tp='App::PropertyFloat',group=None):
 
 _makeProp('Tolerance','','App::PropertyPrecision','Solver')
 
-class _AlgoBase(with_metaclass(_AlgoType,object)):
+class _AlgoBase(object):
+    __metaclass__ = _AlgoType
     _id = -2
     _common_options = [_makeProp('maxiter',
         'Maximum number of function evaluations','App::PropertyInteger')]
@@ -201,7 +201,8 @@ class _Algodogleg(_AlgoNeedHessian):
 class _Algotrust_ncg(_Algodogleg):
     _id = 10
 
-class SystemSymPy(with_metaclass(System,SystemBase)):
+class SystemSymPy(SystemBase):
+    __metaclass__ = System
     _id = 2
 
     def __init__(self,obj):
@@ -297,7 +298,8 @@ class _MetaType(type):
             return issubclass(cls,_Constraint)
 
 
-class _MetaBase(with_metaclass(_MetaType,_Base)):
+class _MetaBase(_Base):
+    __metaclass__ = _MetaType
     _args = ()
     _opts = ()
     _vargs = ()

system.py

@@ -1,5 +1,4 @@
 import os
-from future.utils import with_metaclass
 import asm3.utils as utils
 from asm3.utils import syslogger as logger, objName
 from asm3.proxy import ProxyType, PropertyInfo
@@ -70,7 +69,8 @@ def _makePropInfo(name,tp,doc=''):
 
 _makePropInfo('Verbose','App::PropertyBool')
 
-class SystemBase(with_metaclass(System,object)):
+class SystemBase(object):
+    __metaclass__ = System
     _id = 0
     _props = ['Verbose']