Allow other browserified packages to require lz4
Allow other browserified packages to require lz4

Added a browser field to package.json so that browserify can resolve the correct version of ./lib/utils.js on the browser. This simplifies the build process for packages requiring lz4.
pierrec/node-lz4,pierrec/node-lz4,pierrec/node-lz4,kripken/node-lz4,kripken/node-lz4,kripken/node-lz4,kripken/node-lz4,pierrec/node-lz4