Use call_param for deducing type better.
Correct variadic based fusion::deque requirements
Fix out of bounds access within {front|back}_extended_deque with empty deque.

The insertion point is not correct with empty deque since the range
{next_down, next_up} is not half-open range.
Fix overload resolution failure.

Because the ctor `deque(U &&...)` is also performed as `deque(U const&...)`.