node-gyp error in travis build for node 4.0 & 4.1
<p>When I run a travis build, I get the following error when it attempts to run node-gyp on node version 4.0 and 4.1.
0.12 and lower don't seem to have these issues and build fine. I'm not sure if its a compiler issue here?</p>

<pre><code>&gt; bcrypt@0.8.5 install /home/travis/build/me/api/node_modules/bcrypt
&gt; node-gyp rebuild
make: Entering directory `/home/travis/build/me/api/node_modules/bcrypt/build'
  CXX(target) Release/obj.target/bcrypt_lib/src/blowfish.o
  CXX(target) Release/obj.target/bcrypt_lib/src/bcrypt.o
  CXX(target) Release/obj.target/bcrypt_lib/src/bcrypt_node.o
In file included from /home/travis/.node-gyp/4.1.2/include/node/node.h:42:0,
                 from ../node_modules/nan/nan.h:24,
                 from ../src/bcrypt_node.cc:1:
/home/travis/.node-gyp/4.1.2/include/node/v8.h:336:1: error: expected unqualified-id before ‘using’
/home/travis/.node-gyp/4.1.2/include/node/v8.h:469:1: error: expected unqualified-id before ‘using’
/home/travis/.node-gyp/4.1.2/include/node/v8.h:852:1: error: expected unqualified-id before ‘using’
In file included from ../node_modules/nan/nan.h:184:0,
                 from ../src/bcrypt_node.cc:1:
../node_modules/nan/nan_maybe_43_inl.h:13:1: error: expected unqualified-id before ‘using’
../node_modules/nan/nan_maybe_43_inl.h:16:1: error: expected unqualified-id before ‘using’
../node_modules/nan/nan_maybe_43_inl.h:19:12: error: ‘Maybe’ does not name a type
../node_modules/nan/nan_maybe_43_inl.h:24:12: error: ‘Maybe’ does not name a type
../node_modules/nan/nan_maybe_43_inl.h:31:1: error: ‘MaybeLocal’ does 
In file included from ../node_modules/nan/nan_converters.h:59:0,
                 from ../node_modules/nan/nan.h:189,
                 from ../src/bcrypt_node.cc:1:
../node_modules/nan/nan_converters_43_inl.h:18:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;v8::Boolean&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:19:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;v8::Number&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:20:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;v8::String&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:21:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;v8::Object&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:22:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;v8::Integer&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:23:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;v8::Uint32&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:24:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;v8::Int32&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:34:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;bool&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:35:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;double&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:36:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;long int&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:37:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;unsigned int&gt;’ does not name a type
../node_modules/nan/nan_converters_43_inl.h:38:1: error: ‘return_t’ in ‘struct Nan::imp::ToFactory&lt;int&gt;’ does not name a type
In file included from ../node_modules/nan/nan.h:190:0,
                 from ../src/bcrypt_node.cc:1:
../node_modules/nan/nan_new.h: In function ‘v8::Local&lt;T&gt; Nan::imp::To(v8::Local&lt;v8::Integer&gt;) [with T = v8::Integer]’:
../node_modules/nan/nan_new.h:21:32: error: no matching function for call to ‘To(v8::Local&lt;v8::Integer&gt;&amp;)’
../node_modules/nan/nan_new.h:21:32: note: candidate is:
../node_modules/nan/nan_converters.h:53:38: note: template&lt;class T&gt; typename Nan::imp::ToFactory::return_t Nan::To(v8::Local&lt;v8::Value&gt;)
../node_modules/nan/nan_new.h: In function ‘v8::Local&lt;T&gt; Nan::imp::To(v8::Local&lt;v8::Integer&gt;) [with T = v8::Int32]’:
../node_modules/nan/nan_new.h:28:30: error: no matching function for call to ‘To(v8::Local&lt;v8::Integer&gt;&amp;)’
../node_modules/nan/nan_new.h:28:30: note: candidate is:
../node_modules/nan/nan_converters.h:53:38: note: template&lt;class T&gt; typename Nan::imp::ToFactory::return_t Nan::To(v8::Local&lt;v8::Value&gt;)
../node_modules/nan/nan_new.h: In function ‘v8::Local&lt;T&gt; Nan::imp::To(v8::Local&lt;v8::Integer&gt;) [with T = v8::Uint32]’:
../node_modules/nan/nan_new.h:35:31: error: no matching function for call to ‘To(v8::Local&lt;v8::Integer&gt;&amp;)’
../node_modules/nan/nan_new.h:35:31: note: candidate is:
../node_modules/nan/nan_converters.h:53:38: note: template&lt;class T&gt; typename Nan::imp::ToFactory::return_t Nan::To(v8::Local&lt;v8::Value&gt;)
</code></pre>