Add sanitise.py, a script that does sanitisation and archival

This implements: https://trac.torproject.org/projects/tor/ticket/13563
Additionally add example data.
You need to write every report entry into a separate YAML Document as is defined in http://yaml.org/spec/1.2/spec.html#document//.

Basically what this means is that every time you write an entry into the YAML file you must write:

```
report_file_sanitised.write("---\n")
report_file_sanitised.write(yaml.safe_dump(e))
report_file_sanitised.write("...\n")
```

In the end they should appear in the `exampledata/sanitised/2012-01-01T120000Z_AS3.yamloo` as 

```
---
+input_hashes: [595c8ad9b63ff9f142eca6296021990df6367ab03b3c4eb1c69a8747f0cd41a1]
+options: [-f, bridges.txt]
+probe_asn: AS3269
probe_cc: IT
probe_city: null
probe_ip: 127.0.0.1
report_file: IT/2012-01-01T120000Z_AS3.yamloo
software_name: ooniprobe
software_version: 1.0.2
start_time: 1407420650.560137
test_name: bridge_reachability
test_version: '0.1'
...
---
{bridge_address: null, bridge_hashed_fingerprint: a491b59b16b6fdb59f0b67efcfc95a7b52ac8fcd,
  distributor: tbb, error: null, input: a491b59b16b6fdb59f0b67efcfc95a7b52ac8fcd,
  success: true, timeout: 120, tor_log: null, tor_progress: 100, tor_progress_summary: Done,
  tor_progress_tag: done, tor_version: 0.2.4.20, transport_name: obfs3}
...
---
{bridge_address: null, bridge_hashed_fingerprint: a491b59b16b6fdb59f0b67efcfc95a7b52ac8fcd,
  distributor: tbb, error: null, input: a491b59b16b6fdb59f0b67efcfc95a7b52ac8fcd,
  success: true, timeout: 120, tor_log: null, tor_progress: 100, tor_progress_summary: Done,
  tor_progress_tag: done, tor_version: 0.2.4.20, transport_name: obfs3}
...

```