Fix EXC_BAD_ACCESS from copying block after the matcher is freed

After updating to 0.2.2, I ran into some `EXC_BAD_ACCESS` errors in [-applyMatcher:to:](https://github.com/specta/expecta/blob/c57bd8b9cafe3b3614ce1b9fc35693b46eae3588/src/EXPExpect.m#L95-L96). My theory was that the matcher got prematurely freed somewhere.

Within `_EXPMatcherImplementationEnd`, the matcher is freed before the block gets a chance to retain it (since blocks only retain captured objects when copied). Moving the block copy earlier than the release seems to fix the issue.