Revision 38801

Reduce by 40% the time taken GetEntry for a branch created using a leaflist (exclusive of the decompression time).

Cache the current basket and its limit.
Reorder the set of test to reduce the number of conditional jump in the most common cases
and use:
  #define unlikely(expr) __builtin_expect(!!(expr), 0)
  #define likely(expr) __builtin_expect(!!(expr), 1)
to tell the compiler/processor which branch is more likely.
Record whether the buffer's map of classname and object is used to avoid resetting unnecessarily at read time.