Added autoloading information

When using the annotations of this bundle, one has to update the autoloader. Same when creating custom annotations.

This line is present in the SE `autoload.php` file, but should be added when not using the SE.
merged branch trompette/patch-1 (PR #219)

This PR was merged into the master branch.

Discussion
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Added autoloading information

When using the annotations of this bundle, one has to update the autoloader. Same when creating custom annotations.

The needed line is present in the SE `autoload.php` file, but should be added when not using the SE. For instance, when setting up a demo app for bundle testing with Behat.

Commits
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1fd4ec3 Added autoloading information