setColour Error In paragraph.py

```
File "/Users/martinpacker/md2pptx/md2pptx", line 960, in renderText
    addFormattedText(p, bullet[1])
  File "/Users/martinpacker/md2pptx/paragraph.py", line 612, in addFormattedText
    setColour(font.color, italicColour)
    ^^^^^^^^^
NameError: name 'setColour' is not defined
```

Possibly needs to be made global - as this works in the `md2pptx` part itself.