Start work on interactive commands (//help, //biomelist, //pos1/2)
Added clipboard and world remapping (between mcpe/pe)
//schematic remap
//anvil remapall
Added anvil -> leveldb converter (run Nukkit jar or /anvil2leveldb)
Added safe zstd decompressor
Angle mask fixes
Fix paste air issues with fawe format (which no-one uses anyway)
Fix cfi file:// with an absolute path
FIx schematic format and addBlocks
Update forge to 1.12
Fixes#663
Switched to MemoryOptimizedHistory without compression by default. The
increase in cpu is negligable but the reduction in memory is
substantial. Further compression can still be enabled.
