test opengl examples on linux

[yxnan]

Tested files:

1. examples/opengl-demo-ffi-lsp.txt (on Linux 32/64-bit (AMD) minimum version newLISP 10.7.0)
2. examples/opengl-demo-ffi.lsp (on Linux 32/64-bit (AMD) minimum version newLISP 10.7.0)
3. examples/opengl-demo.lsp (on Linux 32-bit (AMD) minimum version newLISP 10.7.5)

Fixed some typos.

[coveralls]

Coverage remained the same at 0.0% when pulling f85298c on sakamitz:develop into 9eb8f27 on kosh04:develop.

[codecov-io]

Codecov Report

Merging #16 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           develop     #16   +/-   ##
=======================================
  Coverage     67.9%   67.9%           
=======================================
  Files           15      15           
  Lines        15826   15826           
  Branches      2283    2283           
=======================================
  Hits         10746   10746           
  Misses        4374    4374           
  Partials       706     706

---

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 9eb8f27...f85298c. Read the comment docs.