Update Link to regression test matrix in README

Boost.StaticAssert has been merged into Boost.Config, so remove
the dependency.

…ssert

Remove dependencies on Boost.StaticAssert

The three-argument overload documents `\param last2`, but its parameters
are `first1`, `last1`, `first2` — `last2` is a local variable computed
inside the body. The four-argument overload right above it documents
`last1` correctly.

Both `\fn` lines also spell the first two parameters `first` and `last`
while the declarations use `first1` and `last1`.

…-param-names

[doc] Fix the parameter names documented for is_permutation