Update mediainfo{-gui} and dependencies

* mediainfo{-gui} 0.7.73 -> 0.7.74
* libmediainfo    0.7.73 -> 0.7.74

From the mediainfo ChangeLog:
```
Version 0.7.74, 2015-05-25

+ FIMS: Preliminary version (not for production)
+ D-10 audio: display of real bitrate beside the encoded bitrate
+ VC-3: detection of CDP packets (608/708 captions), created by Nexio, inside the VC-3 private data
+ AES3: generic term AES3 replaced by more precise SMPTE ST numbers (302, 331, 337)
+ NUT: basic detection
+ FFV1: more parsing of the bitstream, support of any version of FFV1 in MOV and Matroska
+ DPX: color space and frame rate
x #B906, Matroska: duration was missing if Info block is at the end of the file
x #B908, AC-3: bit depth removed
x #P86, MPEG-4: moov_trak_edts_elst Atom was ignoring version of the atom
x Dolby E: the MXF channel count value was sometimes reported instead of the real channel count
x VorbisComment: WAVEFORMATEXTENSIBLE_CHANNEL_MASK "0X" ("x" in uppercase) is accepted now
x EBUCore: TotalProgrammeDuration was wrongly filled with IdentClockStart value
x EBUCore: Source/Material moved from timecodeStart to timecodeTrack
x MPEG-4: info is missing for some streams in some specific cases
```