inlined ~AssertionHandler(), and changed getConfig to return
shared_ptr const reference instead of by value (very expensive for
shared_ptr's).
Further work on #1086.
Brings test from 0m20.635s to 0m17.186s
- this file excluded from the CATCH_CONFIG_DISABLE_MATCHERS path.
- matchers are always compiled in to the impl file
- _THROWS_WITH macros are still available with matchers disabled - but only the ones that take a string
- tests that use matchers have #ifdefs, so the whole SelfTest project can compile with matchers disable.