
Rewrite sparsetable to use the new common io routines in
hashtable-common.h.  This saves a bunch of boilerplate.  The
only potential downside is the new endian-writing routines
call the underlying file read()/write() a byte at a time
instead of 4 or 8, causing extra syscalls.  But since we only
do like 3 or 4 of these per serialization, it's not a big
deal.

There's also an 'upside' in that the old
{read,write}_metadata and {read,write}_nopointer_data now
support io to C++ streams.

R=austern,igorginzburg
DELTA=228  (4 added, 188 deleted, 36 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=3602


git-svn-id: d91c195d0dee77733e8a5b834c574b2604517118@90 21bedea4-f223-4c8b-73d6-85019ffb75a9

queba/sparsehash,maolin-cdzl/sparsehash,benvanik/sparsehash,maolin-cdzl/sparsehash,benvanik/sparsehash,mabels/sparsehash,queba/sparsehash,mabels/sparsehash,maolin-cdzl/sparsehash,queba/sparsehash,mabels/sparsehash,benvanik/sparsehash