Isolate the "search" and "id_list" methods in their own functions,

Isolate the "search" and "id_list" methods in their own functions,
instead of performing them bodily within dispatchCRUDMethod().

This change is part of a project to refactor oils_cstore.c, in order
to make some of its functionality available to the new query
builder service.

Also: added some comments, and tinkered with others.

M    Open-ILS/src/c-apps/oils_cstore.c

git-svn-id: svn://svn.open-ils.org/ILS/trunk@15999 dcc99617-32d9-48b4-a31d-7c20da2025e4