Merge branch 'develop'

* develop: (350 commits)
  Updates to confirm with OpenSCAD 2021.01
  Added new openscad-amu 'buildinfo' component.
  Improve support for openscad-nightly install.
  Conform to new OpenSCAD .zip dir name for cygwin distribution.
  Update for Debian and move prerequisite check to openscad-amu.
  Don't setup openscad-nightly by default.

.gitignore

@@ -1,8 +1,8 @@
-#
-# database source directory
+G#
+# library contributions
 #
 
-/database_src/
+/contrib/
 
 #
 # backup, build, and release directories
@@ -19,12 +19,12 @@
 /work/
 
 #
-# GitHub docs related
+# GitHub Pages
 #
 
-/docs/Gemfile
-/docs/Gemfile.lock
+/docs/.bundle/
 /docs/_site/
+/docs/_staging/
 
 #
 # eof