Improve repo guess

[coagulant]

Even when package is not hosted on github, search might suggest similar packages or forks.

Examples of bad guesses:

• "BeautifulSoup":https://github.com/bdoms/beautifulsoup
• "MySQL-python":https://github.com/farcepest/MySQLdb1

Solutions:

• do not search GH at all (pros: no mistakes, cons: no way to get extra data for package; are there other ways to figure out package repo?)
• make intelligent guess (parse sources, etc)