Test: Add unit tests for SteamChatBot

Add unit tests for the SteamChatBot module. These tests are used to
validate the SteamChatBot.Connect() for three use cases: when the user
provides a username and password and no sentry file exists; when the
user provides a username, password, and Steam Guard code and no sentry
file exists; and when the user provides a username and password and a
sentry file exits.
Test: Add Travis CI support