Bump chisel3 and firrtl (#1536)

chisel3 changes:
* Direct translation of ChiselIR to FIRRTL
* Driver support for emitting Protobuf
* Better error message for calling return in a when block

firrtl changes:
* Escaped single quotes supported in ExtModule RawParams
* Partial fix to RemoveWires when reg depends on wire
* Parser performance improvements
* Protobuf serialization and deserialization
* Fix annotation renaming for empty aggregates
* Improved code generation for smem wmode and [w]mask ports
* InferWidths performance improvement
* Some user errors no longer reported as "internal errors"
* Add annotation for combinational dependencies between top-level ports
* InstanceGraph is now deterministic