Fixed inner_ext_node_recursive() to work with functions that lack functors

This pull request fixes an issue with inner_ext() so that the method can be used with functions that lack a functor. In inner_ext_node_recursive(), it changes the method to compute children coefficients from project() to unfilter(). This allows us to use inner_ext() on functions that lack functors. It seems to be faster this way too. Also changed test_inner.cc to demonstrate inner_ext() on a function that lacks a functor.