Modify alphabet to m_alphabet to match rest of coding style
Modify alphabet to m_alphabet to match rest of coding style

bradparks/ChaiScript__cplusplus_scripting_language,kamilzubair/ChaiScript,lefticus/ChaiScript,bradparks/ChaiScript__cplusplus_scripting_language,kamilzubair/ChaiScript,lefticus/ChaiScript,kamilzubair/ChaiScript,bradparks/ChaiScript__cplusplus_scripting_language,lefticus/ChaiScript