[NTFS] - Begin to implement B-Trees. Allow for creating several new files in a directory.

NtfsAddFilenameToDirectory() - Add CaseSensitive parameter. Update to use new B-Tree code: First, the index is read and converted to a B-Tree in memory. Next, a key for the new file is inserted into the tree. Finally, the tree is converted back to an index root attribute which is written to disk.
+btree.c - Includes functions related to B-Trees (AKA B*Trees).
ntfs.h - Added several structures for representing B-Trees in memory.
Known limitations: For simplicity, only trees with a depth of one are currently supported (i.e. an ordered list of filenames). Directories that have or will require an index allocation to store all their filenames are still TODO. As a consequence, the user will only be able to create about 6 files in a directory.

svn path=/branches/GSoC_2016/NTFS/; revision=75223

drivers/filesystems/ntfs/attrib.c

@@ -1566,6 +1566,12 @@ GetStandardInformationFromRecord(PDEVICE_EXTENSION Vcb,
     return NULL;
 }
 
+ULONG GetFileNameAttributeLength(PFILENAME_ATTRIBUTE FileNameAttribute)
+{
+    ULONG Length = FIELD_OFFSET(FILENAME_ATTRIBUTE, Name) + (FileNameAttribute->NameLength * sizeof(WCHAR));
+    return Length;
+}
+
 PFILENAME_ATTRIBUTE
 GetBestFileNameFromRecord(PDEVICE_EXTENSION Vcb,
                           PFILE_RECORD_HEADER FileRecord)