1.0.0

• Added onComment option to parser config
• Added support for break and skip values in walk() to control traversal
• Added List#reduce() and List#reduceRight() methods
• Bumped mdn-data to 2.0.12
• Exposed version of the lib (i.e. import { version } from 'css-tree')
• Renamed HexColor node type into Hash
• Removed element() specific parsing rules
• Removed dist/default-syntax.json from package
• Fixed Lexer#dump() to dump atrules syntaxes as well
• Fixed matching comma separated <urange> list (#135)