FLVSplitter: improved AAC detection in files

This is a backport from MPC-BE r2274
Merge pull request #56 from vBm/master

FLVSplitter: improved AAC detection in files
sync resources
installer: update Chinese Simplified translation
PPageExternalFilters: Cosmetics

* Remove an unneeded call to EnableToolTips.
* Add some asserts.
Some testing on SetAlwaysOnTop. (not working)
PPageExternalFilters: cosmetics.

* Use more meaningful functions names.
* Use correct visibility for the members variables and functions.