added config option for cursed earth particles, closes #58

[SanAndreaP]

PS: Please consider disabling transitive dependencies on Tinkers' Construct, as it downloads 2 versions of JEI in dev, crashing the game when trying to test stuff:

    deobfCompile("slimeknights:TConstruct:1.12-2.7.2.508") {
        transitive = false
    }