Comparision of null values to allow null values in enum schemas

[heneke]

No description provided.

[coveralls]

Coverage decreased (-0.04%) to 91.908% when pulling 037e3e8 on heneke:enum_null_value into 57052ce on everit-org:master.

[erosb]

Hi! I've just pushed an other fix of #126 into master : 60cbcca .

I find it a bit more appropriate than yours (bit more tests and a bit better place for the fix), although this PR would also be sufficient.

I'm closing this PR. Do you need an urgent release with this fix? If you don't need any specific release number then you can just use the fixed version by referring to the commit hash of the fix:

        <dependency>
            <groupId>com.github.everit-org.json-schema</groupId>
            <artifactId>org.everit.json.schema</artifactId>
            <version>60cbcca1887949f5935b6989d5a579746330cc2f</version>
        </dependency>

[heneke]

No offense taken – you know the codebase way better than me.