http.rb does not do this on its own.

Turns out http.rb does not support celluloid i/o andymore and we were not making
use of it anyway.

Here's what https://github.com/httprb/http/wiki/Thread-Safety says:
(NOTE: this gem previously supported Celluloid::IO, but that support was removed to add the current timeout backend. It may be added back in a future version)

So now we have a plain http.rb adapter and use that as the default.
This prevents actors from crashing in the adapter (as we don't have any).

require all the things we depend upon where we depend upon them.

These warnings were showing on gitlab ci.

$ bundle exec rake test
/usr/local/bin/ruby -w -Ilib:test -I/builds/leap/nickserver/vendor/ruby/2.1.0/gems/rake-11.2.2/lib /builds/leap/nickserver/vendor/ruby/2.1.0/gems/rake-11.2.2/lib/rake/rake_test_loader.rb test/**/*_test.rb
/usr/local/lib/ruby/gems/2.1.0/gems/bundler-1.12.5/lib/bundler/rubygems_integration.rb:468: warning: method redefined; discarding old find_spec_for_exe
/usr/local/lib/ruby/site_ruby/2.1.0/rubygems.rb:261: warning: previous definition of find_spec_for_exe was here
I, [2016-08-26T15:34:46.162843 #325]  INFO -- : Celluloid 0.17.3 is running in BACKPORTED mode. [ http://git.io/vJf3J ]
/builds/leap/nickserver/test/unit/request_handler_test.rb:28: warning: mismatched indentations at 'end' with 'def' at 21
/builds/leap/nickserver/vendor/ruby/2.1.0/gems/celluloid-io-0.17.3/lib/celluloid/io/ssl_socket.rb:22: warning: instance variable @npn_protocols not initialized
/builds/leap/nickserver/vendor/ruby/2.1.0/gems/celluloid-io-0.17.3/lib/celluloid/io/ssl_socket.rb:22: warning: instance variable @npn_select_cb not initialized
Run options: --seed 61653

# Running:

.................../builds/leap/nickserver/vendor/ruby/2.1.0/gems/celluloid-io-0.17.3/lib/celluloid/io/ssl_socket.rb:22: warning: instance variable @npn_protocols not initialized
/builds/leap/nickserver/vendor/ruby/2.1.0/gems/celluloid-io-0.17.3/lib/celluloid/io/ssl_socket.rb:22: warning: instance variable @npn_select_cb not initialized
.../builds/leap/nickserver/vendor/ruby/2.1.0/gems/celluloid-io-0.17.3/lib/celluloid/io/ssl_socket.rb:22: warning: instance variable @npn_protocols not initialized
/builds/leap/nickserver/vendor/ruby/2.1.0/gems/celluloid-io-0.17.3/lib/celluloid/io/ssl_socket.rb:22: warning: instance variable @npn_select_cb not initialized
.................

Finished in 2.029982s, 19.2120 runs/s, 10.8375 assertions/s.

This became possible because we now use celluloid.
Celluloid handles asynchronity without the need for callbacks
or blocks.

some tests are still broken. But at least they are running now.