Updated Greek translation.

Refs: #1680.
Blacklist Accusoft PICVideo M-JPEG Codec 2.1 since causes a DEP crash.

Newer versions of the decoder have a different CLSID and don't crash.
Cosmetics: add missing brackets and consistently use .0f instead of .f.
Some testing on SetAlwaysOnTop. (not working)
Apply the "Repeat" option after "Play next in the folder". (WIP)

The repeat option will now take effect after the next file in the folder was played (similarly to playlist items).

This commit fixes #978.