Cleanup & standardize config file

changes:

- -sample-config will now comment out all but a few default plugins.
- config file parse errors will output path to bad conf file.
- cleanup 80-char line-length and some other style issues.
- default package conf file will now have all plugins, but commented
  out.

closes #199
closes #944

plugins/inputs/disque/disque.go

@@ -24,9 +24,8 @@ type Disque struct {
 
 var sampleConfig = `
   ## An array of URI to gather stats about. Specify an ip or hostname
-  ## with optional port and password. ie disque://localhost, disque://10.10.3.33:18832,
-  ## 10.0.0.1:10000, etc.
-
+  ## with optional port and password.
+  ## ie disque://localhost, disque://10.10.3.33:18832, 10.0.0.1:10000, etc.
   ## If no servers are specified, then localhost is used as the host.
   servers = ["localhost"]
 `