Removed auth kwarg from low(); lowdata already supports auth kwargs
Added wrapper methods for local and runner client commands

These don't take args or kwargs yet.
Add custom header with the auth token if available
Pull the auth dictionary out of the salt-api return dictionary
Update libpepper call to use local() method instead of old cmd()
Shuffle things in the req() method around a tad for clarity
Add libpepper-specific Exception subclasses
Refactor pepper CLI script; absorb pepper.cli shared lib

There isn't much common functionality between the various scripts.
Reading a user's config file should be in libpepper.
Pass logging level along to httplib to debug HTTP request/response

Looks like there's no better way to do this with urllib2. Refs #10.