logbin v2.0.5

• Fixed reparameterisation for factor variables in method = "cem" (@jakobschoepe, #3)
• Implemented a more efficient approach to parameter expansion (using the transformation matrix).
• When using the parameter expansion approach, check convergence of the reduced parameter vector. As an indirect result, the conv.test function is no longer exported.
• Fixed error in logbin if offset provided
• Implement coeftrace via turboEM::turboem argument keep.paramval, to avoid taking a different path when it is turned on (#5)