tools: remove "addon.gypi" and "gyp_addon"

They've been merged into `node-gyp` and aren't serving any purpose
in the node repo. Fixes #3760.

tools/addon.gypi

@@ -1,24 +0,0 @@
-{
-  'target_defaults': {
-    'type': 'loadable_module',
-    'product_extension': 'node',
-    'product_prefix': '',
-    'include_dirs': [
-      '<(node_root_dir)/src',
-      '<(node_root_dir)/deps/uv/include',
-      '<(node_root_dir)/deps/v8/include'
-    ],
-
-    'conditions': [
-      [ 'OS=="mac"', {
-        'libraries': [ '-undefined dynamic_lookup' ],
-      }],
-      [ 'OS=="win"', {
-        'libraries': [ '-l<(node_root_dir)/$(Configuration)/node.lib' ],
-      }],
-      [ 'OS=="freebsd" or OS=="openbsd" or OS=="solaris" or (OS=="linux" and target_arch!="ia32")', {
-        'cflags': [ '-fPIC' ],
-      }]
-    ]
-  }
-}

tools/gyp_addon

@@ -1,42 +0,0 @@
-#!/usr/bin/env python
-import os
-import sys
-
-script_dir = os.path.dirname(__file__)
-node_root  = os.path.abspath(os.path.join(script_dir, os.pardir))
-module_root = os.getcwd()
-if sys.platform == 'win32':
-  output_dir = os.path.join(module_root, 'build')
-else:
-  output_dir = 'build'
-
-sys.path.insert(0, os.path.join(node_root, 'tools', 'gyp', 'pylib'))
-import gyp
-
-if __name__ == '__main__':
-  args = sys.argv[1:]
-  addon_gypi = os.path.join(node_root, 'tools', 'addon.gypi')
-  common_gypi = os.path.join(node_root, 'common.gypi')
-  config_gypi = os.path.join(node_root, 'config.gypi')
-  args.extend(['-I', addon_gypi])
-  args.extend(['-I', common_gypi])
-  if os.path.exists(config_gypi):
-    args.extend(['-I', config_gypi])
-  args.extend(['-Dlibrary=shared_library'])
-  args.extend(['-Dvisibility=default'])
-  args.extend(['-Dnode_root_dir=%s' % node_root])
-  args.extend(['-Dmodule_root_dir=%s' % module_root])
-  args.extend(['--depth=.']);
-
-  # Tell gyp to write the Makefile/Solution files into output_dir
-  args.extend(['--generator-output', output_dir])
-
-  # Tell make to write its output into the same dir
-  args.extend(['-Goutput_dir=.'])
-
-  gyp_args = list(args)
-  rc = gyp.main(gyp_args)
-  if rc != 0:
-    print 'Error running GYP'
-    sys.exit(rc)
-