A method on the xunit task could set the skip_test_fail property. Fixes #21
Revert "A method on the xunit task could set the skip_test_fail property. Fixes #21"

This reverts commit 35ac689572102e4993ceda9b8542ff523385857b.
Merge branch 'master' of https://github.com/Albacore/albacore into dev