fix icons

[gcampo88]

• [ ] play button is larger than skip button
• [x] back-5 button actually goes back 10 sec
• [x] 5 and 30 don't look completely centered within their circles ?
• [x] subscribe and share buttons are having their border cut off at bottom

[kookster]

On mac os safari, cut off as well, and fonts look off

[gcampo88]

(Some fixes have addressed some of these over past few months)