Disable resolv-replace for ruby 1.9.3

@see issue with spork https://github.com/sporkrb/spork/issues/133
Merge pull request #13 from hooktstudios/spork-1.9.3-patch

Disable resolv-replace for ruby 1.9.3
Added changes so far (or planned changes) for 1.6.0.
Updated require statements for http tests.
Updated dev dependency and home page in gemspec.
Windows dependency change and a minor update for win32-security.
Updated require statements in test files for test-unit.
add Gemfile for bundler
fix broken test
add support for proxies to Net::Ping::HTTP

It now inspects the http_proxy, https_proxy and no_proxy environment variables and behaves accordingly.
use gemspec for bundler
one more tweak to Gemfile
remove comments from tests
set an attribute to indicate if a ping request was proxied
Merge pull request #15 from 6fusion/master

add support for proxies to Net::Ping::HTTP
Force HTTPS rubygems source
Add missing rake development dependency
Markdownify the README