Cell font has incorrect name

[sethk]

Describe the bug
Two problems here: Firstly this error message claims spuriously that DejaVuSansCondensed.ttf can't be loaded:
21:01:47.545 [AWT-EventQueue-0] ERROR org.datavyu.util.ConfigProperties - Error, unable to load font /fonts/DejaVuSansCondensed.ttf. The error is java.io.IOException: Problem reading font data.
Unfortunately that log message is hard-coded, and the real missing font is unifont.ttf. It's missing because the actual name is unifont-10.0.07.ttf. This has always broken and maybe the code should just be removed? See the attached screenshots for what it would look like to load the correct font on macOS.

To Reproduce
Steps to reproduce the behavior:

1. Launch Datavyu
2. Look at the console output

Expected behavior
Either the fonts should load or the correct error message should be logged.

Screenshots
With the current fonts on macOS (generally seems to look better):

With the corrected unifont path:

Desktop (please complete the following information):

• macOS 10.15.5
• Datavyu 1.5.1-SNAPSHOT