apply some minor improvements
I saw the LC_ID_DYLIB items in the output of otool -L command, so I thought
they were needed to be printed (double-checked with cctool source code, version 862).
I have removed this, anyway.
The file mach-o/loader.h states that struct fvmlib is obsoleted,
so there is no need to add the support for LC_IDFVMLIB and LC_LOADFVMLIB.