Issue Description: When zooming the map player markers lag behind.

• Dynmap Version: 3.7-beta-4-935
• Pastebin of Configuration.txt: https://pastebin.com/5SETL3z2
• Steps to Replicate:

• Log in & open map in the browser
• Zoom using scroll wheel or + / - buttons
• You will see that players are legging behind and will return to their correct after exactly 0.6 seconds

[x] I have looked at all other issues and this is not a duplicate
[x] I have been able to replicate this