Un-name unreferenced argument
Don’t assume that ::abc::_std == ::std in abaclade/stl/tuple.hxx
Add abc::to_str_backend specialization for {std,abc::_std}::tuple
Add test case for abc::to_str() of tuple
Simplify abc::_scope_trace using tuples internally
MSC16 does not support default template arguments
Reuse abc::_sequence_to_str_backend from abc::_vector_to_str_backend
Simplify design of abc::_scope_trace_impl
Minor optimization and code documentation fix
Improve code documentation
Merge remote-tracking branch 'origin/master' into python2.7