cstool details does not show total length of each instruction

[BAEGregS]

Feature

• New architecture module
• Support for processor extension
• Add more instruction details (elaborated below)
• Binding support for: language
• Other (elaborated below)

Describe the feature you'd like
For cstool details, add a line to show the length of the instruction/data unit. I suggest "Len: <bytes>" since that is how the information is stored in the cs_insn structure size field.

Additional context
Add this line before the final printf("\n"); in print_details() function in cstool/cstool.c:

    printf("\tLen: %d\n", ins->size);