RangeEditor Exception and Crash in TableEditor

When using either a Range trait in an ObjectColumn in a TableEditor or a trait with a RangeEditor in an ObjectColumn, exceptions are thrown when trying to update the cell colors and python.exe crashes with the Range trait when setting the value outside the acceptable range.

Traits/TraitsUI 4.4 on Windows 7.

``` python
import traits.api as tr
import traitsui.api as trui

class Row(tr.HasTraits):
r=tr.Range(low=0.0,high=10.0, desc='Crashes python.exe when editing outside of range')
f=tr.Float(desc='Always throws AttributeError [control is None] when trying to set cell color')

table_editor = trui.TableEditor(
columns = [trui.ObjectColumn(name='r', label='Range', style='text'),
trui.ObjectColumn(name='f', label='Float w/ RangeEditor',style='text',
editor=trui.RangeEditor(low=0.0,high=10.0)),
],
)

class Table(tr.HasTraits):
rows = tr.List(Row)
view = trui.View(trui.UItem('rows@',editor=table_editor),
resizable=True,
)

t=Table()
t.rows.append(Row())
t.rows.append(Row())
t.configure_traits()
```