Powerup spawns

Powerup locations in a map are defined by the file. Below is an example of a valid .json file. If there is a syntax error in a .json file, it will not be used by Fortress Blast to spawn powerups, but it will be treated as a valid file by ConVars.

{    "flipx": false, "flipy": true, "centerx": "0.0", "centery": "0.0", "1-x": "64.0", "1-y": "0.0", "1-z": "0.0", "2-x": "0.0", "2-y": "64.0", "2-z": "0.0" }

In order to ensure a valid .json file, the following rules should be adhered to:
 * If flipping is required, keep the flipping and map center attributes on the topmost content line. Otherwise, the entire line and its attributes can safely be removed.
 * Keep the X-axis, Y-axis and Z-axis coordinate attributes together in triplets on each other content line, in order from 1 onwards.
 * Make sure to place a comma at the end of every content line except for the last.