make build work on latest versions of node

- bundle giflib with project
- update to giflib 5.0.0 api
- use bindings module to load bindings

binding.gyp

@@ -0,0 +1,31 @@
+{
+  'targets': [
+    {
+      'target_name': 'gif',
+      'sources': [
+        'src/animated_gif.cpp',
+        'src/async_animated_gif.cpp',
+        'src/buffer_compat.cpp',
+        'src/common.cpp',
+        'src/dynamic_gif_stack.cpp',
+        'src/gif.cpp',
+        'src/gif_encoder.cpp',
+        'src/module.cpp',
+        'src/palette.cpp',
+        'src/quantize.cpp',
+        'src/utils.cpp'
+      ],
+      'dependencies': [
+        '<(module_root_dir)/deps/giflib/giflib.gyp:giflib'
+      ],
+      'cflags_cc!': [ '-fno-exceptions' ],
+      'conditions': [
+          ['OS=="mac"', {
+              'xcode_settings': {
+                  'GCC_ENABLE_CPP_EXCEPTIONS': 'YES'
+              }
+          }]
+      ]
+    }
+  ]
+}