- Allow implementing modules that use exportable tables to use hook_schema() (and thus change management via hook_update_N) on data managed tables.
- Make CTools a hard dependency. It has been a matter-of-fact dependency before, requiring it simplifies code.
- Add a .install to data_ui_test module: required for simpletest to set up and break down cleanly.

All tests passing. However, there remains a problem with occasionally illegal table definitions generated by fields generator in data_ui.test.

Fix race condition when exposing schemas, remove stray error output, unserialize schema info when not using ctools.

Move data_alter_table() back into data_ui as it requires too specific arguments - clearly a helper function.