Add a config file to Pigeon Plink with steppings

[kockie69]

Add a config file that will be read during startup or when a PP module is added. If no config file is available, the default settings will be used, otherwise the config will be read as configured.
The configuration will be in json format, and for the default settings it would look like:

{
"steppings": [
{
"name": "None",
"values": [
]
},
{
"name": "legacy",
"values": [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16
]
},
{
"name": "Legacy+Sub",
"values": [0.125,0.25, 0.5, 1.00,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16
]
},
{
"name": "Octaves",
"values": [0.125, 0.25, 0.5, 1.00, 2.00, 4.00, 8.00, 16.00, 32.00
]
},
{
"name": "Digitone",
"values": [0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, 2.00, 2.25, 2.50, 2.75, 3.00, 3.25, 3.50, 3.75, 4.00, 4.25, 4.50, 4.75, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, 8.00, 8.50, 9.00, 9.50, 10.00, 11.00, 12.00, 13.00, 14.00, 15.00, 16.00
]
},
{
"name": "DX11",
"values": [0.50, 0.71, 0.78, 0.87, 1.00, 1.41, 1.57, 1.73, 2.00, 2.82, 3.00, 3.14, 3.46, 4.00, 4.24, 4.71, 5.00, 5.19, 5.65, 6.00, 6.28, 6.92, 7.00, 7.07, 7.85, 8.00, 8.48, 8.65, 9.00, 9.42, 9.89, 10.00, 10.38, 10.99, 11.00, 11.30, 12.00, 12.11, 12.56, 12.72, 13.00, 13.84, 14.00, 14.10, 14.13, 15.00, 15.55, 15.57, 15.70, 16.96, 17.27, 17.30, 18.37, 18.84, 19.03, 19.78, 20.41, 20.76, 21.20, 21.98, 22.49, 23.55, 24.22, 25.95
]
},
{
"name": "DX7",
"values": [0.50,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32
]
}
]
}