add missing package

component-flatten package is needed in bin/component-duplicates
fix typo and use better options in component-build help example

typo: 'gudie' instead of 'guide' in bin/component-open
example: use --standalone instead of --umd since umd is now an alias of standalone
Merge pull request #510 from wryk/fix/dependencies

add component/flatten, update component-build help example, fix typo