UglifyJS requires Node.js to run, but it's a lot faster than Google's compiler and produces smaller gzipped sizes. Some of the non-gzipped sizes are a bit larger than Google's but I think the gzipped size is more important. Faster runtime is also good when we start testing the minified versions too.
This fixes a bug with the usage of `require` in env-js, such that env-js now uses proper relative paths rather than unshifting "." onto `require.paths`. The behavior of `require` is documented here: <http://nodejs.org/docs/v0.4.2/api/modules.html#all_Together...> With this change in place, it's now possible to use env-js simply by require'ing it from a script, rather than having env-js host and eval. Also, this commit changes the initialization of env-js, such that the initial document is immediately available when the env-js module is loaded. And, the event loop is disabled so that env-js shuts down cleanly. This probably breaks some parts of env-js, but it makes it much easier to use so I'm going to play with it a bit.
D3 now supports Sizzle, preferring Sizzle to the native Selectors API if Sizzle is available. Sizzle internally uses the native Selectors API and thus this should have minimal performance implications; also, it allows you to use Sizzle proprietary extensions such as ":first". This commit also restricts the definition of the enter selection so that only append and insert operations are defined. The other operations were generally unsupported anyway, and it cleans up the code to have separate implementations for insert and append. (I might enable additional operations in the future, such as `filter`, `sort` and `each`, but this seems like a reasonable first pass.)