Fixed the requirements in the subtree splits
bug #954 Fixed the requirements in the subtree splits (stof)

This PR was squashed before being merged into the 2.0.x-dev branch (closes #954).

Discussion
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Fixed the requirements in the subtree splits

They should use Pimple 2.1, not 1.0

Commits
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6d1ad87 Fixed the requirements in the subtree splits