omit bc timestamp test (potsgres) on 1.7.3 due an issue with `Date.new(0)`
reported as https://github.com/jruby/jruby/issues/652
these comments are no longer relevant as we try to lazy load the holy 3
roll with an update AR-4.0 (Rails master)
[postgres] restore PostgreSQLColumn.new < 4.0 compatibility
fix running `rake rails:test` tasks + add requires e.g. for JSON
better compatibility with native MySQL/SQLite3 adapter (constants)
update test output (for tracking fialures) from running against 3-2-stable