hdf5_ep

[svn-r25109] Description:
    Bring r25084, 25088, 25092, 25097 from trunk to 1.8 branch:

r25084:
    Begin process of migrating from using property list IDs internally to the
library to using the internal generic property list data structure.

r25088:
    Introduce "file I/O info" struct, to hold file & dxpl pointers, and start
propagating up through library.

r25092:
    More migration to using H5F_io_info_t pointers and away from using
property list IDs internally.  Also, clean up some compiler warnings in the
cache code.

r25097:
    Make progress toward moving from DXPL IDs to property list structures
within the library.  Also move the signature location code from the H5F
package to the H5FD package, where it's a better fit.  Also, clean up some
more compiler warnings along the way.

Tested:
    Mac OSX/64 10.9.2 (amazon) w/C++, FORTRAN & parallel
    (h5committested on trunk)