hdf5_ep

[svn-r17886] Description:
	Bring r17885 from trunk to 1.8 branch:

	Convert 'huge' fractal heap object management code to use refactored
v2 B-tree routines.

	Also, switch internal representation of 'sizeof_addr' and 'sizeof_size'
in files to be uint8_t's instead of size_t's, since they are stored in single
bytes in the file format.

	Various other minor compiler warning cleanups and error call tweaks.

Tested on:
       FreeBSD/32 6.3 (duty) in debug mode
	(h5committested on trunk