we[?] [nNsxX] [arg] extend write operations (insert instead of replace)

Usage: write extend

• wen <num> insert num null bytes at current offset
• weN <addr> <len> insert bytes at address
• wes <addr> <dist> <block_size> shift a blocksize left or write in the editor
• wex <hex_bytes> insert bytes at current offset
• weX <addr> <hex_bytes> insert bytes at address