../lib/blame.c:344:11: error: implicit declaration of function 'diff_atom_hash_update'

suggested by stsp@; no functional change.

while here also wrap fcgi_send_response to make sure we don't end up trying to send a fcgi record bigger than allowed. ok tracey@

Rather than realloc in fixed-sized blocks, use the 1.5 * allocated scheme when growing the array. This produces fewer allocations and up to 3x speedup on large diffs. ok stsp@

Available to all views; for example, 99g will navigate to line 99 in the file if in a blame view or the 99th commit if in a log view. Includes improvements suggested by naddy and stsp. ok naddy@

ok tracey

ok op@