This is to avoid potential name clashes with any classses named
"action", like what shadowm found in the test suite. (The quick fix of
2012-12-31T05:35:28Z!jt_coding@verizon.net is now reverted in favor of this fix.) One complication
is that there is already an "ai:actions" namespace, so within the "ai"
namespace, the renamed namespace is qualified as "::actions".
This is just the first step in upgrading undo_list, and there are not
many benefits yet. Future steps will add functionality to the class
(right now it is just a wrapper) and improve the interface (the
current interface was chosen to minimize the changes needed to
existing code).
The changes are guarded by the C++ and WML conditional symbol
"EXPERIMENTAL".
The experimental flag is temporarily defaulted off, so those patches
should have no effect on people doing ordinary builds. This may change
once fendrin has the tunnel code fixed and polished.
