Attempt for CORE-4528: Allow hash/merge joins for non-field (dbkey or derived expression) equalities.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59994 65644016-39b1-43b1-bf79-96bc8fe82c15
Fixed CORE-4530: DB_KEY based join of two tables may be ineffective.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59995 65644016-39b1-43b1-bf79-96bc8fe82c15
Make a dbCrypt sample a little more interesting

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59997 65644016-39b1-43b1-bf79-96bc8fe82c15