Fix build issues.

This fixes node-gyp build failure:

  CXX(target) Release/obj.target/nodehun/nodehun.o
../nodehun.cpp: In static member function ‘static v8::Handle<v8::Value> Nodehun::SpellDictionary::New(const v8::Arguments&)’:
../nodehun.cpp:83: warning: suggest parentheses around ‘&&’ within ‘||’
../nodehun.cpp: In static member function ‘static v8::Handle<v8::Value> Nodehun::SpellDictionary::addDictionary(const v8::Arguments&)’:
../nodehun.cpp:231: error: ‘malloc’ was not declared in this scope
../nodehun.cpp: In static member function ‘static void Nodehun::SpellDictionary::addDictionaryFinish(uv_work_t*, int)’:
../nodehun.cpp:269: error: ‘free’ was not declared in this scope
make: *** [Release/obj.target/nodehun/nodehun.o] Error 1
make: Leaving directory `/usr/lib/node_modules/nodehun/src/build'
gyp ERR! build error 
gyp ERR! stack Error: `make` failed with exit code: 2
gyp ERR! stack     at ChildProcess.onExit (/usr/lib/node_modules/node-gyp/lib/build.js:267:23)
gyp ERR! stack     at ChildProcess.EventEmitter.emit (events.js:98:17)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (child_process.js:789:12)
gyp ERR! System Linux 2.6.32-358.14.1.el6.x86_64
gyp ERR! command "node" "/usr/bin/node-gyp" "build"
gyp ERR! cwd /usr/lib/node_modules/nodehun/src
gyp ERR! node -v v0.10.21
gyp ERR! node-gyp -v v0.10.6
gyp ERR! not ok