Fix Range response when requesting the last byte.
Fix Range response when requesting the last byte.

Previously this would happen:
 - Request:
   Range: 10-10
 - Response:
   Content-Length: 0
   Content-Range: 9-9/11

now responds with
 - Response:
   Content-Length: 1
   Content-Range: 10-10/11

Ranges that cannot be satisfied are now also reported (range start greater than the last byte or range start greater than range end).

rejectedsoftware/vibe.d,chalucha/vibe.d,Geod24/vibe.d,gedaiu/vibe.d,etcimon/vibe.d,etcimon/vibe.d