UI improvements for send2cgeo web

[SammysHP]

• "add device" not working as long as the browser is not registered. Maybe remove that part until the browser is registered.
• "no browser name!" – maybe set during registration?
• link and text colors are switched
• not possible to unregister browser (should that be possible?)
• "change browser name": hint of text input is no hint, user must remove it first

[Lineflyer]

not possible to unregister browser (should that be possible?)

I don't think this is necessary.

[rsudev]

not possible to unregister browser (should that be possible?)

I don't think this is necessary.

But it wouldn't hurt either. Makes it simpler for the inexperienced to redo registration in case of issues (and shouldn't be much of an issue to implement either)

[mucek4]

Clear cookies and you are unregistered.