yaml 1.2.0 on Node.js NPM

Support blank lines (#64)
- Add BLANK_LINE nodes to the CST
- Add a boolean property spaceBefore for all AST nodes
- cst: Assign comments & blank lines at end of collection to parent unless sufficiently indented
- Always separate document comments from the rest by a blank line
Add missing YAML 1.1 collections: !!omap, !!pairs, and !!set (#65)
Add tag argument for createNode(), along with its refactored schema-specific implementation (29f399b)
Add optional createNode and nodeClass properties to tag objects (bcb8d9c, 3ae63bc)
Add property based tests using fast-check, thanks to @dubzzz (#62)

Fix parsing of minimal strings: '', '-', '?', ':' (#61)
Revert earlier fix for #48, which is now properly handled thanks to the fix for #57 (#59)
cst/ParseContext: Stop advancing node.range.end past newline (08571ff)
cst/PlainValue: Limit valueRange.end to actual value end (0001333)
cst: Stop breaking the spec by allowing tab indents for map values (572f540)
Stop aliasing Pair comment to the comment of its value (9b49ddb, 6d3cb36):
```
key: # this is now a pair comment
  value
```
Render maps with all null values as ? a\n? b\n or { a, b } (40b7a2a)