Add typed array option, implied by "node" option

Added new env option "typed", that defines the variables for typed
arrays. This option is implied when the "browser" or "node" options
is set, so the obsolete mentions of "DataView", "Uint8Array", etc.
have been removed from the "node" and "browser" envs.

Added unit test to prevent regressions.

(unrelated style fix: "`define:<TAB>`" -> "`define:<SPACES>`" at exports.dojo)