Add zlib library inside the project

This will allow us to build binaries without downloading
zlib. This is especially important for Windows, where
setup_env script can not be executed.
Add libpng library inside the project

This will allow us to build binaries without downloading
zlib. This is especially important for Windows, where
setup_env script can not be executed.
Build with in-repo dependencies

env-setup script is not needed anymore
Support building with MSVC 2012

Few C++ 11 features were sacrificed:
- non-static initializers
- using
- unique_ptr uses get() method because there is
no overloaded ! or bool cast for it.
Update doc
Add windows binaries
Add .npmignore
Merge pull request #4 from bem/feature/libs-in

Support building on Windows