compare compare_items<T>
handler item_handler<T>
iterators used to iterators sets of journal objects
filters derived from item_handler, they morph the result set
output derived from item_handler, these do the printing
Also, created a new 'help' files which contains just Ledger's help text.
This means transactions can only have day-level granularity -- which has
always been the case from an data file point of view. The advantage to this
restriction is that reports will now be immune from daylight savings related
bugs, where a transaction falls to the wrong side of a --monthly report, for
example.
