Snap support

[michaelpeeters]

PRQ for #54

• building: snapcraft

• installing locally for testing: sudo snap install --devmode anthwlock-untrunc_1.0-git_amd64.snap

• running: anthwlock-untrunc options ok.mp4 nok.mp4

• upload to snapstore.io: snapcraft upload anthwlock-untrunc_1.0-git_amd64.snap

on snapstore.io you an manage the snap:

• release version
• create github webhooks to automatically build new versions on git changes

[michaelpeeters]

rebuilt with ffmpeg 3.3.9 support which is apparently more stable

[michaelpeeters]

my own PoC: https://snapcraft.io/michaelp-anthwlock-untrunc

[anthwlock]

done with d7e047d575c9, https://snapcraft.io/untrunc-anthwlock