Merge branch 'develop'

* develop: (203 commits)
  bump version to 7.1.1
  spinner in bootstrap
  spinner
  fontawesome
  Minor fixing
  FIx #5767: bootstrap atkfieldset
  disable buttons on form submit and show spinner on steelblue theme (Fix #5792)
  moved libraries added fontawesome disable buttons on form submit and show spinner (Fix #5792)
  jQuery as global library
  bootstrapdatetimeattribute with disableDates
  Handling additional css classes in box.tpl
  CSS styles moved from stillblue to steelblue
  Action buttons spinner
  Added translations
  Added property in atkListAttribute to render a multiple select also in simple search
  Removed "all" option in extended search
  Added spinner showing next to attributes during dependencies execution
  Using _renderChangeHandler of parent
  Additional image for MRA
  Steelblue/Stillblue themes improvements
  ...
composer
Merge branch 'develop'

* develop:
  DOC changes and bump version 8.0.0
  changes
  composer
  Doc CHANGES

Conflicts:
	composer.json
Merge branch 'develop'

* develop:
  * bugfix: default form action button  triggered * oneToMany grid search: enter button trigger search
  charset utf8 in mysql default config
  charset utf8 in mysql default config
Merge branch 'develop'

* develop:
  * bugfix: default form action button  triggered * oneToMany grid search: enter button trigger search
Merge branch 'master' of ssh://github.com/Sintattica/atk into develop

* 'master' of ssh://github.com/Sintattica/atk:
  composer
Merge branch 'master' of github.com:AndreaCattaneo/atk into develop

* 'master' of github.com:AndreaCattaneo/atk:
  composer
avoid 'Notice: Array to string conversion' message when something doesn't works