Replaced the code examples for `set()` to show that the value parameter is not escaped and thus could pose an SQL injection vulnerability.

This allows a subclass to be used fluently without confusing static
analysis tools.

fixes #2291

getSQLForJoins - infinite recursion if join alias is not unique

All func_get_args() calls have been moved to the top of the methods
because HHVM doesn't keep a copy of the original args for performance
reasons.

See facebook/hiphop-php#1027 for details.

- 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

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

This reverts commit 11111bd7.