Remove "move buffer to next or previous tab" functionality.

I don't use it anymore.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
Merge "Windows and Tabs" section with "Browsing".

And minor doc and whitespace updates.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>