Removed an unused method in AbstractPlatform.

Documentation fixes

- Fixed docblocks
- Removed return statements on void methods
- Cleaned up unused private / local variables
- Fixed license issues
- Removed SVN leftovers
- Fixed doctrine-project.org links
- Added line breaks before return statements

Fix foreign table name quotation in schema table and Sqlite platform

Introduced BC break with databases that switch from case-insensitive
to case-senstive handling when identifier quoting is enabled.

This reverts commit 11111bd7.

Quoting table name

[DBAL-374] Fix asset identfier quotation

Quoting table name to avoid errors with:
SELECT * FROM order;

Correcting reference to VarDateTimeType class.

[DDC-2470, DDC-2441] Use column name instead of alias to modify order by clause

VarDateTime is replaced by correct VarDateTimeType class.

Fix an instance of doubled words in the docs