Update First 4 Chapters,Fix Minor Bugs,Omit inexecutable files.

[nvmexp]

Add suggested parameter in "BeautifulSoup(html, "html.parser"). Fix chapter3/3-siteCrawl.py bugs. Add note about requesting google map api format. Fix chapter4/6-wikiHistories.py and rename it as chapter4/6-wikiHistories-Chinese.py for the quest site "http://freegeoip.net" is no longer in service and replace it with "http://www.ip138.com" which may function well in China district. Add the executable chapter4/6-wikiHistories-no-locations.py which is the same with the code segment in book.