Symfony 4 Compatibility

Merge pull request #17 from emulienfou/master

 Update to be compatible with SF3 and SF4

Enabled vote via ajax

v1.2

Updated doc

Fixed bug for scope non request

Fix Request in scope non request

http://symfony.com/doc/2.3/cookbook/service_container/scopes.html#using-
a-synchronized-service

Added configuration to set the maximum value of the vote

Added max_value configuration

Added configuration to set the maximum value of the vote

Updated symfony version in composer

v1.0.1

Updated symfony version in composer

First release

v1.0

Update view star