Allow Net::HTTP.get, get_response, post, post_form, put to receive URI String

[kyanagi]

We need to pass a URI object to Net::HTTP.get_response (or Net::HTTP.get).

Net::HTTP.get_response(URI('http://www.example.com/index.html'))

With this patch, these methods can receive a URI-string.

Net::HTTP.get_response('http://www.example.com/index.html')

[k0kubun]

For consistency, supporting the same thing for Net::HTTP.post as well might be useful.

[kyanagi]

@k0kubun
Thank you for your suggestion.
I added the same support for Net::HTTP.post and Net::HTTP.post_form.

[tachyons]

This looks cool, @k0kubun Does this have any blockers ?

[k0kubun]

I left a comment because I contributed a similar feature, but I'm not the maintainer. You need to ping the actual maintainer https://github.com/ruby/ruby/blob/master/doc/maintainers.md#libnethttprb-libnethttpsrb after fixing the conflict.

[kyanagi]

I resolved the conflicts.
I also updated the put method, which didn't exist when I created this PR, to accept a String.

@nurse What do you think of this?