Add () and {} key maps to navigate to the previous and next file or hunk in the diff. This required changing Got's diff API to collect line type metadata in addition to the line offsets already produced as prompted by stsp. ok stsp@

ok tracey

../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@

as originally intended by tracey@

fcgi_send_response can end up trying to send big amount of data, in particular when serving blobs. if a write failure occurs, gotwebd and httpd go out of sync and "bad stuff happens". debugged with and ok tracey@

there's no need to distinguish between plain text blob and a binary one in the output, just send it chunk by chunk. ok tracey@

ok tracey@