Fix progress update on Windows

[ldionne]

The progress update was broken on Windows when I removed the dependency on ruby-progressbar. Example of output on Appveyor:

1/10 make_tuple/recursive_tuple.cpp.erb (n = 0)2/10 make_tuple/recursive_tuple.cpp.erb (n = 5)
2/10 make_tuple/recursive_tuple.cpp.erb (n = 5)2/10 make_tuple/recursive_tuple.cpp.erb (n = 5)
3/10 make_tuple/recursive_tuple.cpp.erb (n = 10)3/10 make_tuple/recursive_tuple.cpp.erb (n = 10)
3/10 make_tuple/recursive_tuple.cpp.erb (n = 10)4/10 make_tuple/recursive_tuple.cpp.erb (n = 15)
[etc..]

[ldionne]

After trying several things, I am clueless about the reason for this issue. I will put this issue aside, and if someone is annoyed by it then any help is welcome. It is annoying to pollute our Appveyor logs, but it's also not such a big problem.

[ldionne]

A friend of mine told me to try spamming backspace instead of carriage return to fix this issue. This is a note to self to try that out.