[DBAL-237] Fix bug when removing and adding an index on the same columns that may be part of a foreign key.

[DBAL-211] Fix bug with elements in default schema not filtered for really being in the default search path.

Fix for nasty bug that happens when there are 2 or more schemas with tables that have the same name. Since all the AbstractPlatform classes get only the table name using ALL_* schema tables is dangerous because the owner is never supplied.

The other possible solution is to use the ALL_* tables but in each of the methods to fetch the owner before actualy querying them.

* The old implementation produced invalid SQLite statements for tables with
  a composite primary key, as SQLite cannot have more than one primary key
  clause and autoincrement can only be declared on a single column
* There is currently no way to tell from its pragma if an SQLite column
  auto-increments, therefore enabling it on all primary keys is not accurate
* SQLite primary keys auto-increment anyway (but slightly differently from an
  actual auto-increment column -- not guaranteed unique)