[Flex] Create Custom Component tutorial

- Custom component
http://tutorials.jenkov.com/flex-components/index.html : chart sample

http://www.brooksandrus.com/blog/2008/05/26/adding-styles-to-custom-flex-components/

http://tutorials.jenkov.com/flex-components/component-basics.html

http://tutorials.jenkov.com/flex-components/component-with-data-provider.html

http://www.brooksandrus.com/blog/2008/05/26/adding-styles-to-custom-flex-components/