Make UTF-8 a default codec for strings in the non-gui main.

Refer to https://mailman.videolan.org/pipermail/vlmc-devel/2016-March/001672.html

,

"Qt4 doesn't handle strings as UTF-8 in the default settings. According to VideoLan's documentation[1], it says "As a general rules, all character strings passed to LibVLC should be in UTF-8."
Therefore, by setting QTextCodec::setCodecForCStrings, Qt4 will use UTF-8 and the import error will be fixed."

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>