Allow to pass the token as a env variable.

This enables scp and git push.
Explain how to enable scp and git commands.
Confirm before creating the new user.
Add connection timeout to curl calls.
Add a way to support multiple authy tokens under the same unix account.
Update README file.
Allow to protect users as root.

You can now pass the unix user to the protect sub-command.
Update usage help.
Don't ask token if the user has not enabled it.

In that case we just let the user in.
Clean up all inputs.

We strip single/double quotes, spaces, etc.. from all inputs and
function arguments.
Move run_shell call only when login directive is used.

Only when the ask_token_and_log_user_in returns $ITS_OK_TO_LOG_USER_IN
the user is logged in.
Revert my previous change.
Add more debugging statements.
Rename $DEBUG to $DEBUG_AUTHY.

$DEBUG was too generic and could already exist on people servers.
Also added more debugging statements.
Start to adding some tests.
Fix typo.
Add rake task to prepare the tests.

Add more tests.
Adde more tests for login
Move common code to a helper file.
Add prefix test_ to test files.