Comply with RFC 2616

No entity is created on the server, "POST" should not be used.
Merge pull request #30 from greg0ire/patch-1

Comply with RFC 2616
Disable CSRF protection

It is a filter form, no one is going to make something harmful of it.
Merge pull request #32 from greg0ire/patch-1

Disable CSRF protection
Show how to avoid unwanted validation messages

The use of a custom validation group solves this problem.
Merge pull request #33 from greg0ire/patch-1

Show how to avoid unwanted validation messages
Document newer installation method
Merge pull request #34 from greg0ire/patch-1

Document newer installation method
ignore composer.phar
update composer.json
Merge branch 'master' of github.com:lexik/LexikFormFilterBundle
added a FilterConstants class to regroup operands constants
fix constant name
define FilterOperands as a final class
update doc
Merge pull request #36 from lexik/regroup_constants

Regroup constants
refactored the way to filter through event dispatcher
code cleanup
added Doctrine DBAL supports through ExpressionBuilder classes
optimize Doctrine tests suite