fixes Bug 1083517 - added fetch app

nobody ever uses the HBase_client app, likely because nobody knows about it and it is limited to working with HBase.  The hbase_client_app allows raw_crashes, dumps and processed_crashes to be retrieved from HB using the command line.  This is a very useful debugging and ad hoc analysis tool that will be useless when HB goes away.  

This PR introduces a new app that can fetch crashes from any crashstore:
```
$ socorro_app fetch --help
Application: FetchApp 1.0
get data from socorro

usage:
/home/lars/socorro/scripts/socorro_app [OPTIONS]... fetch [ command [ crash_id [ dump_name ]]]] 

OPTIONS:
...
  --command
    what data to fetch (processed_crash, raw_crash, raw_dump, raw_dumps_as_files)
    (default: processed_crash)
...

$ socorro_app fetch raw_crash e865813a-7bb5-4422-9423-465812141015 --hbase_host=socorro-thrift-stage.zlb.phx1.mozilla.com
{
    "AdapterDeviceID": "NVIDIA Tegra 3",
    "AdapterDriverVersion": "OpenGL ES 2.0 14.01002",
    "AdapterVendorID": "NVIDIA Corporation",
    "Add-ons": "",

```

secondly, take the abbreviations for the socorro_apps (ProcessorApp, CollectorApp, etc) and give them friendlier names: processor,  collector, fetch, ...

I've never used the ```separators``` arg and was going to question this, but https://docs.python.org/2/library/json.html explains why you'd want it when doing ```indent```. Cool.