update version to 1.4.1
[server] Fix password security problems.
* Use PBKDF2+SHA256 for hashing
* Use different salt for each user.
[server] Use prepared statements to access database.
update source version to 1.4.2
[server] Add primary keys for a few tables.
Fix a typo
Silence the annoying "subdir-objects disabled" warning
Add travis-ci script