Stable release v3.4.0

[3.4.0] version bumped

same as 3.0.0 but without it's own JQuery-UI

A few code rewrites to use JQuery-UI version shipped with Prestashop 1.5.

stable but with a shipped JQuery-UI (deprecated)

Released before some rewrites of code to avoid shipping it's own JQuery-UI release, which can introduce new problems.
Stable, but can cause conflicts with other modules using JQuery-UI on back-office.