doc/APIchanges: fill in more missing hash values and dates

all values before 2.5 seem to be filled in now
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

doc/APIchanges

@@ -252,7 +252,7 @@ API changes, most recent first:
   Add av_stream_get_side_data() to access stream-level side data
   in the same way as av_packet_get_side_data().
 
-2014-05-xx - 7336e39 - lavu 52.86.100 - fifo.h
+2014-05-20 - 7336e39 - lavu 52.86.100 - fifo.h
   Add av_fifo_alloc_array() function.
 
 2014-05-19 - ef1d4ee / bddd8cb - lavu 52.85.100 / 53.15.0 - frame.h, display.h
@@ -405,7 +405,7 @@ API changes, most recent first:
 2014-02-19 - f4c8d00 / 6bb8720 - lavu 52.64.101 / 53.3.1 - opt.h
   Deprecate unused AV_OPT_FLAG_METADATA.
 
-2014-02-xx - xxxxxxx - lavd 55.10.100 - avdevice.h
+2014-02-16 - 81c3f81 - lavd 55.10.100 - avdevice.h
   Add avdevice_list_devices() and avdevice_free_list_devices()
 
 2014-02-16 - db3c970 - lavf 55.33.100 - avio.h
@@ -446,7 +446,7 @@ API changes, most recent first:
 2014-01-19 - 1a193c4 - lavf 55.25.100 - avformat.h
   Add avformat_get_mov_video_tags() and avformat_get_mov_audio_tags().
 
-2014-01-19 - xxxxxxx - lavu 52.63.100 - rational.h
+2014-01-19 - 3532dd5 - lavu 52.63.100 - rational.h
   Add av_make_q() function.
 
 2014-01-05 - 4cf4da9 / 5b4797a - lavu 52.62.100 / 53.2.0 - frame.h