Add main declaration to package.json
Add main declaration to package.json

Added main declaration pointing to bootstrap-select entry point to allow bundling via browserify. This will enable the common [vendor browserify recipe](https://github.com/sogko/gulp-recipes/blob/master/browserify-separating-app-and-vendor-bundles/gulpfile.js).
azavea/bootstrap-select,azavea/bootstrap-select