breakpoints 7.x-1.0

Changes since 7.x-1.0-beta3:

• fix generated image style names
• bug fixes
• fixed undefined constant
• #1827756 by das-peter: Fixed export functionality.
• #1783686 by mdrummond: Fixed Incorrect output of picture element.
• #1784584 by jaffaralia | alexharries: Added Show help when no breakpoints are available instead of a broken form.
• Insert and Media integration
• added comments to tests
• no more machine_name
• multiplier as text, coder style
• backported group cloning
• use clone
• export to theme added
• override, reload and revert for theme groups
• Added tests for multipliers
• Added tests for breakpoints provided by modules
• updated import/export tests
• failing test
• code cleanup
• Added simpletests
• Let ctools & drupal_write_record handle the serialisation of properties
• #1710178 by attiks: Cleanup 7.x: make a setting 'hide overridden' breakpoints, on by default
• #1710178 by attiks: Cleanup 7.x: add setting to manage multipliers
• #1710178 by attiks: Cleanup 7.x: clean theme_breakpoints_admin_breakpoints_table