Remove docs and point to ones on dartlang.org.

app/doc/pub-build.markdown

----
-title: "Command: Build"
----
-
-    $ pub build [--mode=<mode>]
-
-Use `pub build` when you're ready to deploy your web app. When you run
-`pub build`, it generates the [assets](glossary.html#asset) for the current
-package and all of its dependencies, putting them into a new directory
-named `build`.
-
-To use `pub build`, just run it in your package's root directory. For example:
-
-    $ cd ~/dart/helloworld
-    $ pub build
-    Building helloworld......
-    Built 5 files!
-
-If the build directory already exists, `pub build` deletes it and then creates
-it again.
-
-To generate assets, `pub build` uses
-[transformers](glossary.html#transformer). Any source assets that aren't
-transformed are copied, as is, into the build directory or one of its
-subdirectories. Pub also automatically compiles your Dart application to
-JavaScript using dart2js.
-
-See [Assets and Transformers](assets-and-transformers.html) for information on:
-
-* Where in your package to put assets.
-* What URLs to use when referring to assets.
-* How to use `pubspec.yaml` to specify which transformers run, and in
-  what order.
-
-Also see [`pub serve`](pub-serve.html). With `pub serve`, you can run a
-development server that continuously generates and serves assets.
-
-## Options
-
-### `--mode=<mode>`
-
-Specifies a transformation mode. Typical values are "debug" and "release", but
-any word is allowed. Transformers may use this to change how they behave.
-
-If set to "release" pub will generate minified JavaScript using dart2js.
-Otherwise, it generates it unminified. Also, in release mode, Pub will not
-include any source .dart files in the resulting build output since they have
-been compiled to JavaScript. In any other mode, the raw Dart files will be
-included.
-
-If omitted, it defaults to "release".