Local database search

[godfuzz3r]

added local database search and argparse menu

[Viralmaniar]

@DrLafa Thanks for looking at my code and making changes to it.

While creating offline rep.json file it throws following error:

[*] Downloading database. Please wait, it may take time. Usually around 5-10 minutes.
[*] 523/523[*] Saving database...
Traceback (most recent call last):
  File "OfflinePasshunt.py", line 124, in 
    main()
  File "OfflinePasshunt.py", line 102, in main
    update_db()
  File "OfflinePasshunt.py", line 75, in update_db
    rep.write(j)
  File "C:\Python36\lib\encodings\cp1252.py", line 19, in encode
    return codecs.charmap_encode(input,self.errors,encoding_table)[0]
UnicodeEncodeError: 'charmap' codec can't encode character '\u2329' in position 38825: character maps to 

Would you be able to look at it and I'll merge the pull request?

Thanks,
Viral Maniar

[godfuzz3r]

added force saving and opening in UTF-8. Now everything should be ok. And added function "update-vendors", which parse vendors from site.