Use `null` comparation instead of `is_null()`
Merge pull request #1093 from malukenho/patch-2

Use `null` comparation instead of `is_null()`
Fix bulk insert code example 

Previous code example did not flush all entities when entity count was not a multiple of batch count.
Merge pull request #1094 from thekeyboardbum/master

Fix bulk insert code example
Merge pull request #1 from doctrine/master

Update from original
Changes for grammar and clarity
Merge pull request #1096 from simonharris/master

Changes for grammar and clarity
Corrected file permissions
Merge branch 'master' of git://github.com/doctrine/doctrine2 into correct_entityrepository_interface