add header text for edit blocks mode
skip instructions popup in edit blocks mode
Merge pull request #995 from code-dot-org/edit_blocks_header

Edit blocks header
add free_play checkbox to artist builder
Merge pull request #996 from code-dot-org/free_play

add free_play checkbox to artist builder [Delivers  #74889828]
Merge pull request #997 from code-dot-org/finished

deploy to level-builder