SFINAE - related tests

[Martin Moene]

Hi Phil,

I wonder if there's a special reason why the SFINAE-related tricky test isn't conditionally compiled:

#ifdef CATCH_SFINAE
  TEST_CASE( "non streamable", "" ) {...}
#endif

cheers,
Martin

[Phil Nash]

Because at this stage I was also testing that the CATCH_SFINAE define was being set correctly.

I'm going to move that test into a separate source file, so it is only included in projects of compilers that support it.

Still working this stuff out.

It looks like what I'm using it for is not supported by even VS2010, so it may be premature yet! (it works with GCC and Clang 4.2. Not tried VS2012 yet - or anything else for that matter).