Item upgrades information and artefacts bonus properties

[NewGrafon]

Need info about weapon classes upgrades and info about artefacts additional properties
Weapon classes upgrades can be presented like this:
weaponClass: {
lvl1: {
damage: '+0.73',
spread: '-0.33'
},
lvl2: {
damage: '+1.62',
spread: '-0.72'
},
...lvlN: {
damage: '+x.xx',
spread: '-k.kk'
}...
lvl15: {
damage: '+30',
spread: '-15'
}
}