Revert "travis: don't test node v0.11 (yet)"

This reverts commit ac510a8694819d6fed395a1054b7e2c05e2d708f.
Revert "Revert "travis: don't test node v0.11 (yet)""

This reverts commit 2695d8586f5ce6b370bfa10676578eec915e6aaa.