Fix a memory leak in error handling when a manifest cannot be parsed.
Be more verbose when catching a Protobuf exception.
Clean up some server code (isolating the POST-validation), added support for the Bjoern WSGI server as an alternative to the reference WSGI server (which is slow).
Several bugfixes:
* When reloading a file's metadata, don't invalidate the manifest if the fs_entry is dirty (i.e. locally-modified, unflushed).
* When reloading a file's metadata, don't reduce its size if the version has not changed (size can only increase).
* Fix memory leak when extracting block info from failed block replicas if an fsync() fails.
* Apply the effect of a trunc() to queued sync_contexts if a trunc() occurs between fsync()'s.
* Bugfixes in the order in which fields are initialized in fs_entry.
* Add some extra debugging information (all around).
* Remove dead code from manifest.
* Correctly synchronize on close, if locally-modified.