[DBAL-555] Improved approach to fix issue from GH-367.
[DBAL-555] replace a bunch of occurances of $diff->name and $diff->newName with quoted identifier version.
[DBAL-555] Fix Sqlite and SQLAnywhere Platforms, document TableDiff changes.
Merge pull request #453 from doctrine/DBAL-555

[DBAL-555] Fix using Identifier assets and quoting