Various tweaks to products grid filters etc.

Trying to troubleshoot some things...think we're good now.  Some of the
changes here were made and then discovered not to be necessary yet, but
left in place since they're probably good ideas anyway.

tailbone/newgrids/alchemy.py

@@ -104,6 +104,7 @@ class AlchemyGrid(Grid):
             factory = filters.AlchemyDateFilter
         elif isinstance(column.type, GPCType):
             factory = filters.AlchemyGPCFilter
+        factory = kwargs.pop('factory', factory)
         return factory(key, column=column, **kwargs)
 
     def iter_filters(self):

tailbone/newgrids/core.py

@@ -55,7 +55,7 @@ class Grid(object):
         self.data = data
         self.main_actions = main_actions
         self.more_actions = more_actions
-        self.joiners = joiners
+        self.joiners = joiners or {} # use new/different empty dict for each instance
 
         # Set extra attributes first, in case other init logic depends on any
         # of them (i.e. in subclasses).

tailbone/newgrids/filters.py

@@ -128,7 +128,7 @@ class GridFilter(object):
     value_renderer_factory = DefaultValueRenderer
 
     def __init__(self, key, label=None, verbs=None, value_renderer=None,
-                 default_active=False, default_verb=None, default_value=None):
+                 default_active=False, default_verb=None, default_value=None, **kwargs):
         self.key = key
         self.label = label or prettify(key)
         self.verbs = verbs or self.get_default_verbs()
@@ -136,6 +136,8 @@ class GridFilter(object):
         self.default_active = default_active
         self.default_verb = default_verb
         self.default_value = default_value
+        for key, value in kwargs.iteritems():
+            setattr(self, key, value)
 
     def __repr__(self):
         return "GridFilter({0})".format(repr(self.key))