add start|stop|restart|run to crono executable

this is done using daemonize gem, but it is not breaking the old
interface. But sets a deprected comment to the old one daemonize
process.

crono.gemspec

@@ -30,4 +30,5 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'sinatra'
   spec.add_development_dependency 'haml'
   spec.add_development_dependency 'rack-test'
+  spec.add_development_dependency 'daemons'
 end