[GH-146] auto-quote table and column name in Connection->delete/insert/update()

This issue is created automatically through a Github pull request on behalf of nicolas-grekas:

Url: https://github.com/doctrine/dbal/pull/146

Message:

I wonder why quoting of table/column names in Connection->delete/insert/update() is left to the developer and not not done internally by the library?

I made a patch to allow the lib to quote table and column names in a backward-compatible way. I believe that if this feature is not already in the lib, there must be some reason, but I can't understand it right now, nor find a reference to any rational.

Would it be possible to elaborate the reason if possible, while accepting / rejecting the pull request at your will of course?

Many thanks.