{lib}mediainfo{-gui}: 0.7.80 -> 0.7.81

Built and run locally.

From the Changelog:
```
Version 0.7.81, 2015-12-31

+ Acquisition Metadata: support of all SMPTE RDD18 elements
+ Matroska: cover presence and content of the cover, thanks to Max Pozdeev
+ #F446, Matroska: Handling of cropping values, thanks to Max Pozdeev
+ Improvement of Python binding: Mac Os X support, Python2 and Python3
  can use same MediaInfoDLL.py
+ #F484, AVI: OpenDML Interlaced / Progressive scan type detection
+ MP4: support of AtomicParsley imdb tag
x #B959, MPEG-TS: MPEG-1 Video appeared as MPEG-2 Video
x #B914, Matroska: Undefined number of chapters in some M4V with Timed
  Text, thanks to Max Pozdeev
x #B962, Matroska: negative timecodes were not correctly handled
x #B964, FLV: was hanging trying to open some FLV files
x JPEG in AVI or MOV: better handling of buggy APP0/AVI1, avoiding some
  false positives about interlacement
x DVCPRO HD: some containers consider DVCPRO HD as with width 1920
  despite the fact it is 1280 or 1440, using 1280 or 1440 in all cases
```