nx-mongo: - optional support for mongodb connection pools (compile time macro USE_CLIENT_POOL controls this, per default, this is on) - allow to pass "-metadata" to gridfile::create to ease metadata attachment to gridfiles - some conveniance improvements in nx-mongo.tcl (ability to ignore attributes in "bson encode", ability to unset attributes in gridfs, ...) - bump version numbers of nsfmongo to 0.3 and nx-monogo to 0.5