BaseException.message is deprecated in Python 2.6 and gone in 3
Merge branch 'master' into HEAD

Conflicts:
	elftools/common/utils.py
Use integer division in Python 3

This means DwarfConfig.default_address_size is now an integer in Python 3, as
in Python 2.
Implement Section.__hash__() to avoid Python 2’s DeprecationWarning
Avoid BytesWarning in debugging messages in Python 3
Drop unused imports