Build node-marisa-trie for Linux, Windows and OS X with node-gyp.

Recently I need to use marisa trie in a cross-platform app built with node-webkit. Your previous work on node-marisa-trie makes this possible with just a new gyp build script and a few changes in the source code.

Though it now builds without problem on Linux and OS X, I failed to link node-marisa-trie to a prebuilt static library on Windows. To work around this, I imported a copy of libmarisa source code and introduced a new gyp target 'libmarisa' as a dependency. Anyway, there is not a system directory for libraries on Windows, so this change can make installing on Windows easier.

I'm not sure if you have plans to update this Node.js package, but it would be very much appreciated if you can take time to review my changes, and to help make it support more platforms in the next release.