Bring over HFS+ fixes.
Bring over NTFS fixes.
Rename FSDirectory ID and add in support for looking up child entries via their ID. Code review changes.
Bring over ext2/3/4 fixes:

ext2: Change inode from an int to long. Add support for creating an ext2 file from an inode but without an Ext2Entry.
ext4: Add support for reading file systems created with the flex_bg feature.
ext4: Detect multi-mount protection file systems. Add some tests for large directories and MMP.
Bring over IBM partition table fixes: Add more IBM partition table checks.
Bring over file system & partition test cases and test data.