[AD] datafile cache

[VERSTEEGH@xxxxxx]

Shawn wrote:
>    Add caching system to speed up filename#object and
>   load_datafile_object() (damn, this one has been in the list for nearly
>   a year now :-)
Which is partially my fault (I promised to do it, and actually had it for 90
percent doen at some point, but then I lost track and time etc.)

I'll try to find the time to do it somewhere in the very near future
;-)

Martijn Versteegh