Adds support for $recursiveAnchor and $recursiveRef

[fdutton]

Resolves #507

[codecov-commenter]

Codecov Report

Merging #835 (ad453f8) into master (4d51a58) will decrease coverage by 0.32%.
The diff coverage is 64.47%.

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@@             Coverage Diff              @@
##             master     #835      +/-   ##
============================================
- Coverage     78.80%   78.48%   -0.32%     
- Complexity     1197     1213      +16     
============================================
  Files           119      120       +1     
  Lines          3822     3891      +69     
  Branches        731      746      +15     
============================================
+ Hits           3012     3054      +42     
- Misses          524      546      +22     
- Partials        286      291       +5     

Impacted Files	Coverage Δ
.../main/java/com/networknt/schema/Version201909.java	100.00% <ø> (ø)
...va/com/networknt/schema/RecursiveRefValidator.java	44.11% <44.11%> (ø)
src/main/java/com/networknt/schema/JsonSchema.java	90.03% <70.58%> (-1.45%)	⬇️
...in/java/com/networknt/schema/CollectorContext.java	77.27% <85.71%> (+0.88%)	⬆️
...main/java/com/networknt/schema/JsonMetaSchema.java	83.46% <100.00%> (+0.13%)	⬆️
...n/java/com/networknt/schema/ValidatorTypeCode.java	96.03% <100.00%> (+0.07%)	⬆️