[ENH] filegals: add support of client cache (with etag and last-modified headers) + reduce download file memory usage + use DB hash for cache key instead of regenerating one + remove useless function and comments + some minor perf improvements
[ENH] filegals: add support of client cache (with etag and last-modified headers) + reduce download file memory usage + use DB hash for cache key instead of regenerating one + remove useless function and comments + some minor perf improvements

git-svn-id: a7fabbc6a7c54ea5c67cbd16bd322330fd10cc35@15620 b456876b-0849-0410-b77d-98878d47e9d5

changi67/tiki,oregional/tiki,changi67/tiki,tikiorg/tiki,changi67/tiki,tikiorg/tiki,tikiorg/tiki,changi67/tiki,oregional/tiki,oregional/tiki,tikiorg/tiki,changi67/tiki,oregional/tiki