-j fails on Yosemite 

```
$ papertrail -j "program:simplepaas-nginx -wp-cron GET myimage"
/Library/Ruby/Gems/2.0.0/gems/papertrail-0.9.10/lib/papertrail/cli.rb:162:in `display_results': undefined method `to_json' for #<Hash:0x007fd1c4263ca0> (NoMethodError)
	from /Library/Ruby/Gems/2.0.0/gems/papertrail-0.9.10/lib/papertrail/cli.rb:119:in `run'
	from /Library/Ruby/Gems/2.0.0/gems/papertrail-0.9.10/bin/papertrail:5:in `<top (required)>'
	from /usr/bin/papertrail:23:in `load'
	from /usr/bin/papertrail:23:in `<main>'
$
```

```
$ sw_vers 
ProductName:	Mac OS X
ProductVersion:	10.10.1
BuildVersion:	14B17
```