vchoi_fork

[svn-r12766] Made two changes to Direct I/O VFD: first added 3 parameters to H5Pset_fapl_direct to control 
memory boundary, file block size, and maximal copy buffer size; second in H5FD_direct_write and
H5FD_direct_read, the library checks whether data buffer is aligned.  If it is, then write and 
read the data directly instead of making a copy buffer.