Add all the A tasks

Task/Abstract-type/PicoLisp/abstract-type.l

@@ -0,0 +1,11 @@
+# In PicoLisp there is no formal difference between abstract and concrete classes.
+# There is just a naming convention where abstract classes start with a
+# lower-case character after the '+' (the naming convention for classes).
+# This tells the programmer that this class has not enough methods
+# defined to survive on its own.
+
+(class +abstractClass)
+
+(dm someMethod> ()
+   (foo)
+   (bar) )