Remove leading jsonschema2pojo from the dir names

It is just making the typing more verbose; no one will confuse which
"cli" directory we're talking about
Specify maven-javadoc-plugin version
Share SchemaStore across the run

But permit the tests to create a new one, to avoid stateful test failures
Having shared SchemaStore breaks the intg tests

Unknown why, so easier to just revert it for now.
Silence compiler warnings
Distinguish between not-found and class-cast ex

Previously the CCE would have just travelled up the stack, so I hope no one was depending on that behavior
Briefly log if skip is engaged

Better to have one message about it than to have a user wonder why the task didn't execute
Throw on collision instead of renaming

This will enable us to track down these problems, instead of them just silently proceeding
Implement v4 required array in terms of v3

Since the v4 just consolidates all the "required" fields into an array, but is otherwise semantically the same as v3, patch up the document to be what `RequiredRule` is expecting.

This was done with document patching since the `apply` signature and `JsonNode` does not permit easily navigating back up to the containing `"properties"` element.

The disadvantage of doing it this way is that if the `JsonNode` is ever printed, it will be clearly not what the user provided and thus potentially confusing.
Correct a javadoc typo
ResolveRefs should recurse against the ref-ed one
Remove needless cast
Disable tests that are not aligned with our goals
Move the groupId to com.radius to show the fork

I have zero belief that these changes will be accepted upstream anytime soon, and we have an immediate need.
Remove the reference to gpg

We don't sign releases and it's just a pain point
[maven-release-plugin] prepare release jsonschema2pojo-0.4.6.1
[maven-release-plugin] prepare for next development iteration
Merge branch 'v4fixes'

This should have landed on master before the release, but I forgot