Cleaned the composer requirements
minor #143 Cleaned the composer requirements (stof)

This PR was merged into the 2.0-dev branch.

Discussion
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Cleaned the composer requirements

The Process and Finder components are left-overs of the custom Phar building (and they should have been dev requirements at this time btw).
The curl requirement is a left-over of Goutte 1.x. It is not a requirement of 2.x anymore.

Commits
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60cbfa4 Cleaned the composer requirements