[constants.py] Add DW_OP_lit2 - DW_OP_lit30, DW_OP_reg2 - DW_OP_reg30, DW_OP_breg2 - DW_OP_breg30.
[dwarfreader.py] Process sections only if present.
Add 'strp' method.
Add 'processPubNames' method.
[encoding.py] Add function 'sint'.
[locinfo.py] Add missing constants.
[Elf.py] Add appropriate exception handling.