Use ruby-bundler package

Instead of the gem hack
add debugger
Split bundler setup to gems.rb

Now it can be used independently without any puavo stuff.
require "puavo/gems"
Add assertive Puavo.resolve_api_server!
Add puavo-feed
puavo-sync-printers: Use assertive api server resolve
puavo-feed: add session todo
puavo-feed: Add --device option
version 1.4.0