testText test case failing

Running on a Fedora 30 VM and a conda env with CQ installed. Wanting to check if this is occurring for others as well.

obj2.val().Volume() appears to be returning 0.
```
======================================================================
FAIL: testText (tests.TestCadQuery.TestCadQuery)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/dev/Projects/cadquery/tests/TestCadQuery.py", line 1880, in testText
self.assertLess(box.val().Volume(),obj2.val().Volume())
AssertionError: 7.999999999999998 not less than 0.0

----------------------------------------------------------------------
```

Using cq-editor to view the created text, it appears the dot in the center of the 0 in '2.0' is not a complete solid.


Interestingly the text has volume by itself, and does effect the volume of the box when cut from it.

```
box = cq.Workplane("XY" ).box(4, 4, 0.5)
obj1 = box.faces('>Z').workplane()\
.text('CQ 2.0',0.5,-.05,cut=True,halign='left',valign='bottom', font='Sans')
obj2 = box.faces('>Z').workplane()\
.text('CQ 2.0',0.5,.05,cut=False,combine=True, font='Sans')
text = cq.Workplane("XY").text('CQ 2.0',0.5,.05,cut=False,combine=False,font='Sans')

print(obj1.val().Volume())
print(obj2.val().Volume())
print(text.val().Volume())

OUTPUT:
7.99308664152082
0.0
0.006833732128143307
```