The 2i work now has tests for removals as well as regex etc.
Some initial refactoring work has also been tried - to try and take some
tasks of the critical path of push_mem. The primary change has been to
avoid putting index keys into the gb_tree, and building the KeyChanges
list in parallel to the gb_tree (now known as ObjectTree) within the
Ledger Cache.
Some initial experiments done as to changing the ETS table in the
Penciller now that it will now be used for iterating - but that has been
reverted for now.
Added basic support for 2i query. This involved some refactoring of the
test code to share functions between suites.
There is sill a need for a Part 2 as no tests currently cover removal of
index entries.
