Add support for Opendylan

[Opendylan](https://opendylan.org) is an object-functional
language originally created by Apple for the Newton. Dylan
is a direct descendant of Scheme and CLOS (without the Lisp
syntax).

Dylan.gitignore

@@ -0,0 +1,16 @@
+# backup files
+*~
+*.bak
+.DS_Store
+
+# project file
+*.hdp
+
+# documentation build directory
+build/
+
+# compiler build directory
+_build/
+
+# dylan tool package cache
+_packages/