DXF import missing colours
<!--
See our full bug reporting guidelines at https://inkscape.org/contribute/report-bugs/
Writing a good bug report will ensure we'll be able to help efficiently. 🙂
-->
#### Summary:
<!-- Summarize the issue/suggestion concisely: -->
If a dxf file is imported into Inkscape the colours of all items are black.
#### Steps to reproduce:
<!-- Describe what you did (step-by-step) so we can reproduce: -->
- Import the attached dxf file
#### What happened?
All items are coloured black.
#### What should have happened?
The colours should be:
Solution: I have changed lines 672 and 676 in the attached file input_dxf.py.
May I ask whether Martin Owens can make these changes, if he agrees with my solution. Many thanks.
Sample attachments:
<!-- Attach the sample file(s) highlighting the issue, if appropriate. -->
[testColors.dxf](/uploads/ec595897992ae612e502be360147f60d/testColors.dxf)
[dxf_input.py](/uploads/5803b60063ac9d976a7fa1da2effbac3/dxf_input.py)
#### Version Info:
```
- Inkscape Version: 1.0 (1.0+r73+1)
- Operating System: Kubuntu
- Operating System version: 18.04
```
<!--
❤️ Thank you for filling in a new bug report, we appreciate the help! ❤️
Please be patient while we try to find the time to look into your issue.
Remember that Inkscape is developed by volunteers in their spare time, we'll try our best to respond to all reports.
-->
<!--
Please be careful when/after writing # for example in logs, code, or versions of linux
- use inline code span - single backticks (`) before and after it, like this - `inbox#1618`
- use multi-line code block - triple backticks (```) to fence/enclose console logs
- attach long logs as a text file.
-->
issue