Added another DROP SCHEMA cross schema group test

Right now this throws an incorrect error
cross schema foreign key & sequence tests
Added @After to check for orphaned storage
Start of making schemaManager drop whole schema
Start of implementation of removing from fdb

pertistit still needs implementing. ALso there's TODOs
Got sequences working

turns out you can't have a cross schema identity column
Made dropAllTables handle cross-group foreign keys

by adding a new method that drops all non-system tables
drop schemas and jars
Handle cross-schema dropping correctly

it was leaving the rows and indexes around, new tests check
that everything is ok.
Cleanup
Simple AbstractStore.removeTrees(..., Schema)

FDBStore overrides it
Renamed to align with current phrasing

trees only really apply to perstit
!= to !...equals()

because they're strings
Cleaned up javadoc
Use Collections.singleton method

so many things to remember
Use index.getIndexName.getFullTableName

that info was hiding in there somewhere
Drop the persistit sequences too (on drop schema)

fdbstore overrides this method
cleanup javadoc
Remove extra parameters on dropSchema
Only mark non-system schemas as affected

when dropping non-system schemas