create a simple cache for storing model hierarchy lookups
create simple methods in a base class for model hierarchy navigation
create a wrapper for hierarchy navigation using different types
adjust PojosImpl to use hierarchy navigator

this will make changes for ticket 11019 easy to implement
change preprocessor to use hierarchy navigator
adjust do-all for change in preprocessor constructor
update preprocessor test class with latest changes
remove weird rebase artifact
replace local function with third-party library function
Merge pull request #2158 from mtbc/trac-11091-hierarchy-navigation

assist #11091: refactor server DB queries for hierarchy navigation (rebased)