xuan

As discussed in [issue](https://github.com/JuliaStats/GLM.jl/pull/273#issuecomment-453688969) #273, the reason why we don't pivot by default is that it would produce inaccurate results by setting argument `check=false`. But now what I use here...

Since the Project.toml is reverted, the Travis CI may fail. It doesn't mean that the code has a bug.

> @jason-xuan Would you have the time to add the comment @andreasnoack requested? I can't do that myself, yet it would be too bad that this PR would be blocked...

> Sure! I'll see if I could figure out how to get a test case from R next week because I'm new to it.

> If you prefer you can give me a Julia example and I'll run it in R for you. Though the syntax is quite close so it shouldn't be too...

@nalimilan I calculated the deviance with RCall and got the following results: ```julia julia> @rput dfrm; R> fit deviance(fit) [1] 138626.5 ``` Compared with `deviance(m1.model)=138626.46758072695`, it seems to be a...