This release took a lot of time ot be published, so the list of new features and fixed bugs is very extensive.
Features
[1f9bbc2] Dropdowns are now displayed with the Select2 library widget (@javiereguiluz)
[09b59a8] Added a toolbar panel + profiler to improve backend debugging (@javiereguiluz)
[f4dd66e] Allowed to define custom field types and options on-the-fly (@ogizanagi)
[fe745cc] Introduced the "template" field option to define a custom template to render the field
[ef5514e] Added support for flash messages (@gabiudrescu)
[48f775c] Improved search engine for numeric search queries (@javiereguiluz)
[6e3c824] Displayed the global form errors (@thomasbeaujean)
[588ac32] Dispatch events in tweaked actions (@thomasbeaujean)
[7561df5] Added support for properties defined using snake_case (@javiereguiluz)
[ef3f59a] Added a link to remove entries of the collections (@thomasbeaujean)
[5fc1a7d] Required only needed Symfony dependencies (@xabbuh, @javiereguiluz)
[f7fb266] Updated Bootstrap, jQuery and FontAwesome (@Pierstoval)
Minor changes and bug fixes
[7c7b52f] Fixed the search engine for PostgreSQL databases (@javiereguiluz)
[ff6f5ef] Added the translations for the field collection action (@thomasbeaujean)
[9d32134] Translated the error (and errors) label of forms (@thomasbeaujean)
[9d6be7e] Trigger events in the ajaxEdit() method to mimic edit() behavior (@javiereguiluz)
[62329ce][a884695] Translated boolean labels (@thomasbeaujean)
[c7339ab] Translated all the remaining labels and messages
[82087d4] Updated the Spanish translation (@javiereguiluz)
[141d648] Updated the German translation (@xabbuh)
[ebf1c71] Moved the detailed error pages from production to development (@javiereguiluz)
[7b7bc1b] Added Catalan translations file (@arnaugm)