- also added docs for exception translators
- updated approvals

- it was forward declared as a class, which caused warnings on some compilers. It should really have been a class anyway.
- this addresses the same issue as PR #534, albeit from the other angle.

I've incremented the minor release number. This is a slight abuse of semantic versioning so let me explain:
I've slightly changed how matchers are used. The matcher macro (REQUIRE_THAT/ CHECK_THAT) used to introduce the Catch::Matchers namespace before the macro token for the matcher, to save you having import the namespace yourself.
The trouble is if the matcher token is not a simple matcher (can now be an expression) this breaks!
So I've removed that qualification. Now if you use Matchers you'll have to do somethings like using namespace Catch::Matchers to bring them in.
This is a breaking change - but, OTTOH, Matchers are an undocumented "beta' feature that I've stated in the past is not guaranteed to have a stable API - so I don't think this warrants a major version change - but I did want to make it significant enough that people do notice that something is going on - and perhaps lead them to this commit message.

(syntactic sugar for AllOf, AnyOf and Not compositional matchers, respectively)

- this could be a breaking change - fixed up self-test code to compensate

(replaces need for PRs #310 and #504)