Remove remaining compilation warnings (issue #72)
Remove remaining compilation warnings (issue #72)

GCC 7.3.0 and clang 4.0.1

WojciechMula/pyahocorasick,WojciechMula/pyahocorasick,pombredanne/pyahocorasick,pombredanne/pyahocorasick,pombredanne/pyahocorasick,WojciechMula/pyahocorasick,pombredanne/pyahocorasick,WojciechMula/pyahocorasick