Introduce a simple serialization framework that basically concatenates
all (sub-)structs of a given item and replaces pointers with offsets.
Use that to switch cache interface from item duplication to serialization
into a buffer & back and allow the new membuffer cache to be used on any
cacheable item.
Where feasible, move the serialization code to svn_temp_serializer.*
Merged revisions from /branches/performance:
981090, 981189, 981194, 983398, 983406, 983474, 983488, 983490, 985603,
986521, 986608, 986832, 987865, 987868, 987869, 987872, 987886, 988898,
990533, 990535, 990536, 1029229
Partially merged:
981204, 981665, 981828
git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/integrate-cache-item-serialization@1068724 13f79535-47bb-0310-9956-ffa450edef68
14 files changed
