Fix some implicit int64 to int conversion warnings. However, the real issue
is that PermutationMatrix mixes the type of the stored indices and the "Index"
type used for the sizes, coeff indices, etc., which should be DenseIndex.
(transplanted from eae4abe46e5b454adfad59f9894f340594c1b9b7)

--HG--
extra : transplant_source : %EA%E4%AB%E4n%5BEJ%DF%ADY%F9%89O4%05%94%C1%B9%B7
Update basicstuff unit test to avoid instantiating the ambiguous sqrt(int)
Update adjoint unit test to avoid instantiating sqrt(int)
Add missing using std::sqrt
Remove the following note made by gcc: "The ABI of passing structure with complex float member has changed in GCC 4.4"
Fix SSE plog<float> to return -INF on 0