Replace rest-client with smth

[Neodelf]

They're using rest-client gem. This is a very heavy-weight library. So I want to replace it with the native ruby library or better http gem.

[pineapplethief]

+1 for http.rb gem

[Neodelf]

@pineapplethief yep, I hope their measuring is correct))

[Neodelf]

I reverted the PR https://github.com/Neodelf/lecter/pull/68 cause there was a problem. Cause HTTP.rb gem has a different interface to add params to the GET request. So a lecter_enabled parameter was not added correctly.