mod_video: fixes for handling binaries returned from the z_string and other function (used to be lists)

(cherry picked from commit a3c234f0f7f68ab17c4dc05a72ff4fb3c3c7212b)

Conflicts:
	modules/mod_video/mod_video.erl
Merge branch 'release-0.10.x' of github.com:zotonic/zotonic into release-0.10.x
core: minor fix in mime-lookup for files not recognized by 'identify'

(cherry picked from commit 911e756157c2c7553add78fbe92acb30b6d85774)