PROTOTYPE
Increments an existing global variable by the specified amount.
| Key | Value(s) | Description | 
|---|---|---|
| method | "IncrementProjectGlobal" | Increments an existing global variable by the specified amount. | 
| key | "keyname" | Name of variable to modify | 
| increment | "value to increment by" | Required. Integer. TODO: Can this be negative? | 
{
  "method": "SetProjectGlobal",
  "key": "myCounter",
  "value": 0,
  "project": "LargeDataSource"
}{
  "method": "IncrementProjectGlobal",
  "key": "myCounter",
  "increment": 1,
  "project": "LargeDataSource"
}
