Implemented vtkBillboardTextActor

[xtanion]

Resolves #465
This PR adds vtkOpenGLBillboardTextActor3D actor.

[pep8speaks]

Hello @xtanion! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2022-01-20 15:12:28 UTC

[codecov]

Codecov Report

Merging #525 (3fc3225) into master (d12f9ed) will increase coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #525      +/-   ##
==========================================
+ Coverage   81.87%   81.95%   +0.08%     
==========================================
  Files          54       54              
  Lines       10618    10685      +67     
  Branches     1069     1076       +7     
==========================================
+ Hits         8693     8757      +64     
- Misses       1661     1663       +2     
- Partials      264      265       +1     

Impacted Files	Coverage Δ
fury/fury/lib.py	100.00% <0.00%> (ø)
fury/fury/actor.py	87.94% <0.00%> (+0.20%)	⬆️
fury/fury/tests/test_actors.py	91.79% <0.00%> (+0.21%)	⬆️