Add ability to restore the auto-commit mode after using DB.open/commit/rollbackTransaction

[eugeneRover]

DB.openTransaction() (and Base.openTransaction() ) method sets Connection auto-commit flag to false.
While this behavior is exactly complies JDBC requirement to begin transaction, there is no way to return auto-commit to true using DB or Base classes.

Also, it worth noticing that Connection is not returned to previous state after commitTransaction/rollbackTransaction operations.
Assuming that Base/DB are the abstractions that are hiding Connection from developer, it becomes non-obvious that something is irreversibly changed inside after commit/rollback.

IMHO, most perfect solution would be remembering and restoring auto-commit flag after commitTransaction/rollbackTransaction.
The definitely must-do is to add setAutoCommit method, something like :

public  void setAutoCommit() {
    try {
        Connection c = ConnectionsAccess.getConnection(name);
        if (c == null) {
            throw new DBException("Cannot setAutoCommit, connection '" + name + "' not available");
        }
        c.setAutoCommit(true);
    } catch (SQLException ex) {
        throw new DBException(ex.getMessage(), ex);
    }
}