Reconnect Interval: set different interval values

The ReconnectInterval setting is currently a simple value, in seconds, e.g. 5. That means that the socket will try to connect each five seconds.
If the distant server never respond, this can lead to a huge amount of tries, processing and resource usage.
The tries interval should be short in the beginning, then get longer.

Here is an example of syntax that could be set instead of a simple value:
ReconnectInterval=6*5;5*15;60
This means that the connect will be tried 6 times each 5 seconds, then 5 times each 15 seconds then each 60 seconds.

Setting a simple value such as:
ReconnectInterval=30
will result in trying each 30 seconds as before.