Added Gitter badge

Reviewed-By: Mikeal Rogers <mikeal.rogers@gmail.com>
Reviewed-By: Rod Vagg <rod@vagg.org>
configure: remove shared cares build option

Bundled cares differs from upstream which will result
in a compilation error when trying to used a shared cares.

Fixes: https://github.com/joyent/node/pull/8786
PR-URL: https://github.com/iojs/io.js/pull/38
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
modules: adding load linked modules feature

- introduced NM_F_LINKED flag to identify linked modules
- setting node_is_initialized after calling V8::Initialize in order to
  make the right decision during initial module registration
- introduced modlist_linked in order to track modules that were
  pre-registered in order to complete it once node is initialized
- completing registration of linked module similarly to the way it's
  done inside DLOpen

PR-URL: https://github.com/iojs/io.js/pull/8
Reviewed-by: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
policy: added contribution policy

Policy originally by @isaacs and @othiym23, submitted by @mikeal,
committed fresh by @rvagg because .. #22 is kind of a mess

PR-URL: https://github.com/iojs/io.js/pull/22
Reviewed-By: Mikeal Rogers <mikeal.rogers@gmail.com>
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: Rod Vagg <rod@vagg.org>