Allow user information for importing database to be filled in manually.

Remove unix-only os module related commands (os.getlogin, etc. are unix-only and
fail on windows user machines.)  Raise an error if the username and email cannot
be found from git alone.  The user is then asked to fill in that information
manually within the importOldDatabase.py script.
Script for creating RMG-Py thermo and kinetic libraries from a valid chemkin file.
Change exception handling for finding username/email from git in importOldDatabase.py
Remove typo. (Connie must have had hats on the mind!)
Change-detection in importOldDatabase script.

It attempts to detect changes since the last import, and set the history items
accordingly. Not really working yet, but I think a good start..