DownloadIndicatorProposal

Shock's DownloadIndicatorProposal

Currently we have 3 download indicators:
1 Red/blue rectangle on the globe

2 Icon in the lower right corner

3 Progressbar near the icon

Changes to 1:
- Show a red rectangle when downloading an image/tile

- Show a blue rectangle when downloading elevation

which means:

- DO NOT show a blue rectangle when loading from disk

- Show a blue rectangle at ANY level when SRTM is downloaded

Changes to 3:
- Progressbar should be above the icon

- Show a red progressbar when downloading an image/tile

- Show a blue progressbar when downloading elevation

in case of multiple downloads (multithread/image+elevation)

- The first bar goes above the icon

- The second bar goes above the first bar

- If the first bar finishes before the second, the entire row should slide down

Colors
Colors must be configurable