walk method for AnyOfValidator not implemented

[bartoszm]

com.networknt.schema.AnyOfValidator is not implementing walk method. It could look like com.networknt.schema.AllOfValidator#walk I suppose

[stevehu]

@bartoszm I have merged some new changes for the walking and it looks like the test case for #451 is broken. Could you please take a look? Thanks.

[ERROR] Tests run: 3, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.015 s <<< FAILURE! - in com.networknt.schema.Issue451Test
[ERROR] shouldWalkAnyOfPropertiesWithWithPayloadAndValidation  Time elapsed: 0.012 s  <<< ERROR!
java.lang.NullPointerException
	at com.networknt.schema.Issue451Test.walk(Issue451Test.java:72)
	at com.networknt.schema.Issue451Test.shouldWalkAnyOfPropertiesWithWithPayloadAndValidation(Issue451Test.java:53)

[prashanthjos]

@bartoszm we left it open because it depends on usecase to uasecase. Please feel free to write your version of walk.