Minor bugfix release and support of traccar v3.3

Today I am pleased to announce support for the version 3.3 of traccar. There is a slight change in the documentation as well.

Also this release includes following bug fixes:

• seamark layer prevented original layers from working (#429)
• vietnamese language was not working on mobile version (#430)
• commands sending was not working on v3.3, CUSTOM commands were not working at all (#440)
• it was possible for a user that does not have access to the device to delete it from database through the API (#507)
• unable to add user through API because password could not be serialized (#509)

Also it contains latest translation updates from transifex project site along with the new 'Romanian' language.