Added more "retrieve" options to DeviceData

* Added a check for `__nfs_data['age'] == 0` at parse time
* Added `get_rpc_op_stats` method and modified the `__print_rpc_op_stats` to use it
* Added a `backlog` method so that it doesn't get calculated in the `display_iostats`
* modified display_iostats to use `self.ops` and `self.backlog`
Added nfsiostat.py

This may not be the right thing to do, but lets try it ;)
Massive rewrite of NFS Stats

* Changed from using a pipe to nfsiostat to using its innards directly
* implemented getting "current" data for nfsiostat data (not since boot/mount time)
* Fixed units per Issue #5
* Attempted modifying the names for the NFS components to make more sense with units
* Added "Volume" to the component name to make room for aggregate data (forthcoming)
* Fixed "precision" of floats `(%7.3f)`
Merge branch 'issue-4-proxy' into nfsiostat
Merge branch 'master' into nfsiostat

Conflicts:
	setup.py
         - just had to re-add the nfsiostat module
Removing extra output that was missed
Merge branch 'master' into nfsiostat
Merge branch 'issue-9-logging' into nfsiostat

Conflicts:
	src/newrhelic.py
Merge branch 'pidfile' into nfsiostat
Merge branch 'issue-9-logging' into nfsiostat
change local print to logger.debug
Merge branch 'issue-13-fedora' into nfsiostat
Merge branch 'spec-rhel5' into nfsiostat
Merge branch 'issue-13-fedora' into nfsiostat

Conflicts:
	newrhelic.spec
Merge branch 'spec-rhel5' into nfsiostat

Conflicts:
	newrhelic.spec
adding nfsiostat to rpm files
Merge branch 'master' into nfsiostat
Added nfs_device_list filter and additional stats
Removing formatting - breaks json

* Apparently if you format floats as strings, it breaks JSON :-/
* Removed the Popen and PIPE (handling that differently)
Merge branch 'master' into nfsiostat