Fix PayloadMatcherTests for generics
Address PR comments and other improvements
* Revert `rawtypes` mode for the `PayloadMatcher`
* Make `HeaderMatcher` as `rawtypes` as well
* Make `MockMessageHandler` expect `rawtypes` for `Matcher`s.
This way we can just support `Matcher`s like `notNullValue(Message.class)`
* Rename `expect()` to `assertNext()`
* Rename `andReply()` to `thenReply()`
* Track replies are supplied in the `MockMessageHandler`
* Distinguish simple `MH` from the `MP` types in the
`MockIntegrationContext#instead()` do not let to replace simple `MH`
with fully configured `MockMessageHandler` or any other `MP` implementation.
Fail replace if types mismatch; wrap `MockMessageHandler` to simple `MH`
if it doesn't have replies when we are going to replace simple `MH`
* Wrap `MockMessageHandler` to the `Mockito.spy()` in the
`MockIntegration#mockMessageHandler()` to allow to `verify()` interaction
in the test-case
Remove wrapping `MockMH` to raw `MH` when no reply supported.
If `MockMH` isn't supplied with replies ti's safe to use it as is - no harm to target endpoint
which supposed to be last one in the flow
Some polishing and JavaDocs
More JavaDocs
Add docs for the `MockMessageHandler` and fix some JavaDocs
Make the `MockMessageHandler` with an API like:
```
MockIntegration.mockMessageHandler()
.handleNext(Consumer<Message<?>>)
.handleNext(Consumer<Message<?>>)
.handleNextAndReply(Function<Message<?>, Object>)
.handleNext(Consumer<Message<?>>)
.handleNextAndReply(Function<Message<?>, Object>)
.handleNextAndReply(Function<Message<?>, Object>);
```
Doc Polishing
079ccb84e2