Add disasm libs

[tvorogme]

This is not the best way, but it's really helpful. Please notice me, if it's needed in main repo.

The main problem is that a lot of users use PUSHREF in mainnet to load libs, and current disassembler not disassemble them. The one way it can be done is follow: check if cell is special, and if it is, and we know such lib - add lib disassemble to code.

Also, I've added <spec to load special cells as slices, it might be needed :)

Before:

(592A3699870F04DA0FFDF26D0FF47AD0684F5B48B4FBB144854397FBFD2EA46C) PUSHREF
BLESS
EXECUTE

After:

// LIB: DA2BB4D0547F78C3B2199F9815274E14BB1F31F737F71B0572039980F5B6F9C4 
    0 SETCP
    19 (xC_) DICTPUSHCONST
    DICTIGETJMPZ {
      0 => <{
        70 PUSHINT
        DIV
      }>
    }
    11 THROWARG
(592A3699870F04DA0FFDF26D0FF47AD0684F5B48B4FBB144854397FBFD2EA46C) PUSHREF
BLESS
EXECUTE