Revert "Update usage.md"

This reverts commit 5c83de9f8f6d428914ffbe7d2db9162c49076523.
Revert "Update crossdomain.xml"

This reverts commit 09303df2bc01c5752d41cc73705fa339090d4ea5.
Revert "Update html.md"

This reverts commit 67e8e4f4ddc6d08cf42f2620ee485baff8bd6918.
Revert "Update faq.md"

This reverts commit 2d074e936e8df3978b92023eb5effb99fd054d5c.
Revert "Update extend.md"

This reverts commit 139a0311f0c747d896766f30c0752140014102d1.
Revert "Update css.md"

This reverts commit 9d321004be4d926b8ebc701aa811d401c356d4c4.
Revert "Update crossdomain.md"

This reverts commit b049a5d42cc3e296f303188db63afd39c1aa1753.