archive: ArchiveEntry now a mememto and not exposed directly
typedefs for boost::shared_ptr
fixed up dir_util to new interface
add "FileProvider" that does Load/Store and indicates Precedence
vfs: structure has changed. one RealDirectory per OS dir; vfs_tree
stores it; populate uses it to Add() stuff to vfs_tree; lookup does path
traversal and calls populate
This was SVN commit r5499.
