1. In osrfListSetDefault(): install the standard function

1. In osrfListSetDefault(): install the standard function
free() as the default item-freeing callback function,
instead of the gossamer-thin and useless wrapper for it,
osrfListVanillaFree().  This change eliminates a layer of
function call overhead.

2. Eliminate osrfListVanillaFree() as neither used nor useful.

3. Add doxygen-style comments to document every function.

git-svn-id: svn://svn.open-ils.org/OpenSRF/trunk@1766 9efc2488-bf62-4759-914b-345cdb29e865