Getting Started Difficulty Ports' Description

[AlphaSerpentis]

Taking a peek into the code, I noticed that the values to determine if a port is "Low/Med/Ultra" is dependent on specific values. This should be changed by determining the set of ports' difficulty value and arrange their settings as so.

Take the following example:

Port 1 - Diff. 1 -> 256
Port 2 - Diff. 256 -> 1028
Port 3 - Diff. 1028 -> 1056784

Expected Port Description:
Port 1 is LOW
Port 2 is MED
Port 3 is ULTRA

Actual Port Description (this is an example):
Port 1 is MED
Port 2 is ULTRA
Port 3 is LOW

[AlphaSerpentis]

PR #6 should fix this.