Resolves#610.
`RageSoundReader_MP3` has three different methods of setting the position. The default choice of `SetPosition_toc` is unable to provide an accurate result. The reason Edit Mode has such a severe desync when working with MP3's is due to the preference of using `SetPosition_toc`.
We can prevent this by using `SetPosition_hard` which works very well. Judging by comments in the file, it seems like `SetPosition_hard` was too resource intensive to use as the default method, 20+ years ago.
The only downside is, if you start from an arbitrary position (which is **only** possible in Edit Mode), you have a few milliseconds of corrupted audio, but then the sync is perfect. You can hear this in the demonstration video below.
When we start from the beginning of a file, such as playing a song, or using `Play whole song` in edit mode, `MADLIB_rewind` will be used.
`SetPosition_hard` provides an accurate result, and is consistent with the offset provided by `MADLIB_rewind`. The result is a consistent sync experience whether the MP3 is started from the beginning, or from an arbitrary position midway thru the file.
The `m_bAccurateSync` boolean dependency has been removed from SetPosition since it does not seem to provide any benefit on modern hardware. It seems fine to remove it so that we can call `MADLIB_rewind` or `SetPosition_hard` as fast as possible.
In my testing I never got `SetPosition_estimate` to be used, but I've left it in as a backup option.
sukibaby