Turned ssl_verify attr in client to function

attr was changed to a function so verify mode can be set from Instance's
instances
Changed call to RestClient::Request

Using the proper way to propagate :verify_ssl
Merge branch 'master' of github.com:laclasse-com/ruby-etherpad-lite

* 'master' of github.com:laclasse-com/ruby-etherpad-lite:
  ajout require openssl
  modification variable ssl_verify
  Turned ssl_verify attr in client to function

Conflicts:
	lib/etherpad-lite/client.rb