Removed broken link and picture

[kartva]

Removed broken link which is supposed to point to demonstration of Piston backend, which has been removed.

[codecov[bot]]

Codecov Report

Merging #201 (1185178) into master (96d5184) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #201   +/-   ##
=======================================
  Coverage   68.83%   68.83%           
=======================================
  Files          56       56           
  Lines        4313     4313           
=======================================
  Hits         2969     2969           
  Misses       1344     1344           

Impacted Files	Coverage Δ
src/coord/ranged3d/projection.rs	73.86% <0.00%> (-1.14%)	:arrow_down:
src/coord/ranged1d/types/slice.rs	90.90% <0.00%> (+2.27%)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 96d5184...1185178. Read the comment docs.

[jayvdb]

This has been solved on master, and the PR can be closed