+=head2 validate() and @EXPORT transition plan
+
+First (done in 0.36):
+
+validate_card() is the new name for validate(). Both work for now.
+
+New-style usage (not recommended for code that needs to support B:CC before 0.36):
+
+ use Business::CreditCard qw( :NEW );
+
+You get validate_card(), cardtype() and receipt_cardtype(). You can also ask
+for them explicitly / individually:
+
+ use Business::CreditCard qw( validate_card cardtype receipt_cardtype );
+
+
+Second (we're at now now):
+
+Waiting for 0.36+ to become more prevalent.
+
+
+Third:
+
+Recommend new-style usage.
+
+
+Fourth:
+ (this is the incompatible part):
+
+Don't export validate() (or anything else [separately?]) by default.
+
+This is the part that will break things and we probably won't do for a long
+time, until new-style usage is the norm and the tradeoff of breaking old code
+is worth it to stop or namespace pollution.
+