* Tooltip: add 'followCursor' and 'placement' option
When used on a `<span>` with short text but large empty area, the location of the tooltip was at the bottom-center of the area, which isn't ideal.
I think 'followCursor' should be the default, but making it optional for now to minimize testing.
Also added the 'placement' prop -- for the span case again, the mouse cursor is blocking the tooltip.
* View/Follower count: only use compact when > 10k
## Issue
Received complaints -- some people prefer to see full resolution.
## Changes
- As a compromise, we'll only apply the compact notation when the value is greater than 10k, with the exception of Tile View Count, where we'll always apply it due to space limitation.
- Also added Tooltip for Follower count.
## Fixes
- The string was always in 'en' locale in some instances, so it wasn't grouping up digits properly in Japanese (groups of 4), for example.
