Created phpmethod role
merged branch WouterJ/creating_phpmethod_role (PR #4)

This PR was merged into the master branch.

Commits
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ab2c3e7 Created phpmethod role

Discussion
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Created phpmethod role

We already have a `:phpfunction:` and `:phpclass:` role, it would be easy to have a `:phpmethod:` role to link to methods of PHP classes too. (see symfony/symfony-docs#1967 for more information)

This PR creates a basic role. I have copy/past some code from the `:method:` and `:phpclass:` roles to create this function. I just started with Python, so the code can be buggy.
added a composer.json