go.toosl/cmd/present: Remove border from iframes
go.toosl/cmd/present: Remove border from iframes

If the author wants a border they can add it on their own.

LGTM=adg
R=adg
CC=golang-codereviews
https://codereview.appspot.com/107590045

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

webfd/go-zh.tools,8limbs/gotools,skyportsystems/go.tools,d0f/go-zh.tools,d0f/go-zh.tools,bryanxu/go-zh.tools,skyportsystems/go.tools,8limbs/gotools,bryanxu/go-zh.tools,skyportsystems/go.tools,webfd/go-zh.tools,d0f/go-zh.tools,d0f/go-zh.tools,8limbs/gotools,webfd/go-zh.tools,webfd/go-zh.tools,bryanxu/go-zh.tools,bryanxu/go-zh.tools,webfd/go-zh.tools,skyportsystems/go.tools,bryanxu/go-zh.tools,d0f/go-zh.tools,skyportsystems/go.tools