Unify windows makefile

[gberaudo]

With a tiny change of the main Makefile it looks possible to handle Windows build.
@kalbermattenm, would you be able to test this change before I merge it?

[kalbermattenm]

I will test it this afternoon and give you a feedback.

Moreover, we discovered with @monodo that it was really easier to code for NGEO in a Linux environment, but I really appreciate being able to build it in Windows.

[kalbermattenm]

@gberaudo, I tested this PR, and I had to apply following change for it to work:

make is not a Windows cmd, it is running inside a Cygwin environment and in Windows, the Python executable is python.exe whatever version you use. Thus if I leave the -python python3, then make tries to use the Python distribution which is installed with Cygwin and this one has not enough rights to write on the disk. So the only thing I did was to be sure to have Python3 in my path.

With these modifications, I am able to run make dist without any error.

But running make serve triggers an weird error and I do not know if that has something to do with Windows or if this is a general error:

[gberaudo]

@kalbermattenm, I updated the PR, could you please test again?

[fredj]

1089 line removed !

[kalbermattenm]

I'll test it again on Wednesday and give you a feedback.

[kalbermattenm]

Weird, I get another error now when running make dist (after make cleanall)

[gberaudo]

@kalbermattenm make dist is broken on all platforms. If it is the only issue, then I will merge.

[gberaudo]

Travis passing, I am going to merge now. @kalbermattenm, let me know if there is something not working on your side and it will be fixed in a follow up PR.