Add test files and .pyc to .gitignore

Signed-off-by: Pamela McA'Nulty <pamela@webreply.com>
o Remove testing stuff from get_credentials()

Signed-off-by: Pamela McA'Nulty <pamela@webreply.com>
refactor top-level code into do_backup() function

Signed-off-by: Pamela McA'Nulty <pamela@webreply.com>
Move download folder name into a testable constant "GMAIL_FOLDER_NAME"

Signed-off-by: Pamela McA'Nulty <pamela@webreply.com>
Automated test function

Signed-off-by: Pamela McA'Nulty <pamela@webreply.com>