Abnormally high memory usage on certain devices #59

When using Macbook with Chrome, the application uses over 1 gig of memory after some usage.

Steps:

1. Open the application in chrome https://map.ubikampus.net
2. Zoom the map out and back in multiple times
3. Open Chrome task manager and inspect GPU process memory usage

Expected: memory usage stays in reasonable limits, around hundreds of MBs.
Actual: the browser’s GPU process consumes excessive amounts of memory: up to 1.5 GB. The application process itself consumes a couple hundred megabytes.

This issue seems to be only on certain devices, so it might be related to certain hardware configurations. Also it seems like the issue is related to the raster layer of the map.

Note: Seems like Maptiler demo maps have the same problem to some extent. Opening https://www.maptiler.com/maps and choosing raster layer also causes suspiciously high memory usage.