We still don't know what the other parameters do, but they appear to be very similar to those of FormatThisUserSaveData.
Most likely FormatThisUserSaveData is just an alias for FormatSaveData with LowPathType Empty
The savedata for each game is stored in /savedata/<ProgramID> for NCCH files. ELF files and 3DSX files use the folder 0 because they have no ID information
Got rid of the code duplication in File and Directory
Files that deal with the host machine's file system now live in DiskFile, similarly for directories and DiskDirectory and archives with DiskArchive.
FS_U: Use the correct error code when a file wasn't found
The 3DS allows the user to read from files opened with the Write access modifier, even if he did not specify the Read access modifier.
Open the files in binary mode so that we can prevent CR/LF problems in Windows, where a line-end is replaced by these two bytes instead of just 0xA, this was causing problems with the GetSize test
For now threads are using their Handle value as their Id, it should not really cause any problems because Handle values are unique in Citra, but it should be changed. I left a ToDo there because this is not correct behavior as per hardware.