Make it possible to run the RG in the uWSGI server
Make the default replication timeout 60 seconds
Ensure that we flush in-core bufferred blocks on write, even if we haven't flushed any of them to disk.  Do so with an fs_entry "dirty" flag.  Also, remove some dead code from the manifest, and make sure that we're updating the modtime on write.
This also (hopefully) fixes the segfault from the demo with Nirav, whereby a failure to replicate a block due to a timeout would cause the error-handling code in close() to try to free an uninitialized md_entry structure.