Rename variables in Quarry to be unique

[Ivan Beschastnikh]

• Quarry flattens scope so we don't know which variable is referenced in a Quarry invariant.
• Daikon does not infer invariants about local variables, but does infer invariants about parameters
• We need to rename parameters to be unique so that invariants are inferred properly

[Issue created by carolemieux: 2015-05-10]