`funcattr` adjustments for usage with rest module

1) Add new calling overload in AttributedFunction so that it won't
try merging parameter and attribute type tuples when incoming and
target parameter type tuples match exactly. In that cases relevant
parameters are simply overwritten by attached attribute functions.

2) Add diagnostic that all attached InputAttribute functions conform
to stored argument list.

3) static imports added for qualified symbols
vibe.http.rest : add `funcattr` support
Add `funcattr` test case to vibe.http.rest suite

Also makes test suite exit upon finish.