Update mpc-hc_setup.iss.

* simplify a preprocessor check
* rename a function
* use a wildcard for the translation dlls
* reindent
installer: remove unneeded strings from Inno Setup's language files
custom_messages.iss: update copyright year
checkyear.sh: add .iss files in the files to check
Updated Swedish translation.
Fix: Prevent the volume OSD message from erasing the filename on startup.

This commit fixes #2985.
SSA subtitles: Fix outline background with \frx or \fry tags.

This commit fixes #2984.
update thirdparty/versions.txt
update Changelog.txt and release date
Update Changelog.txt
bump version to 1.6.7
Updated Greek translation.