hdf5_msb

[svn-r13926] Description:
    Add small interface to "wrap" a static buffer (usually on the stack), but
still allow for buffers larger than the static buffer to be allocated.  This
can eliminate _many_ short-lived buffer allocations in situations where the
buffer is a predictable size (or at least a "very likely" size).

    Also, some minor code cleanups, particularly in the SOHM caching code.

Tested on:
    Mac OS X/32 10.4.10 (amazon)