Remove execute permission on README
Improve RPM to automatically set up an SSH user for remote log collection

When the RPM is installed, it will now create an ‘olpcjournalprocessor’ user
and generate it an SSH key. It will enable that SSH key, but limit it to
executing the olpc-journal-processor script using SSH forced commands.

If the person installing the RPM takes a copy of the generated private key,
they can remotely access the school server to process the logs in future.

Note that this means we need to be careful to not introduce escalation
vulnerabilities (such as shell escapes) in olpc-journal-processor, or it
would be possible for someone to get shell access through the
olpcjournalprocessor user.
Provide defaults for command line arguments to reduce configuration overhead

Allow CSVs to be outputted to stdout by passing ‘-’ as the output file name
(the default). Automatically use /library as the data store root, unless a
different one is specified. Sanity check the given root path to make sure it
looks like a data store.
Allow parameters to be passed to the forced SSH command

This allows invocation to output general statistics, or URI statistics, for
example:
	ssh olpcjournalprocessor@my-server \
		olpc-journal-processor -o - -u /dev/null
vs.
	ssh olpcjournalprocessor@my-server \
		olpc-journal-processor -o /dev/null -u -
Add olpc-journal-aggregator to connect to remote hosts

This will connect to a number of remote hosts in parallel and run
olpc-journal-processor on each of them, then merge the results. It’s designed
as a centralised way to grab data from all of the school servers in a
deployment.