Revision history for Future

0.04    CHANGES:
         * Fix implementation of sequenced futures to work properly on
           immediates
         * Ensure that future->future chaining via callbacks works correctly
           on immediates
         * Link to "curry" in the docs about CODE-returning convenience
           accessors ->done_cb, ->fail_cb and ->cancel_cb

0.03    INCOMPATIBLE CHANGES:
         * Future->needs_all and Future->needs_any now return dependents'
           results

        CHANGES:
         * Removed $future->( ... ) callable override
         * Pass $f1 to ->or_else code block by symmetry with ->and_then
         * Added $f->followed_by
         * Added Future->wait_any dependent future constructor
         * Rearranged documentation and added more examples

0.02    CHANGES:
         * Rearranged non-leaf future logic
         * Added {pending,ready,done,failed,cancelled}_futures accessors
         * Added Future->needs_any constructor

0.01    First version, released on an unsuspecting world.

