Added More Flexible Support for Mac OS X

[kwesiRutledge]

These changes do the following:

1. Correct an issue where the installation failed on Mac OS X.
2. Removed the vendor.json file which does not seem to be used in more recent version of Go.

More on Point 1:
Modified the install.sh file so that it installs both lp_solve and swig via Homebrew. Also, created a new file make_lib.go which is called when the Operating System is found to be Mac OS X. make_lib.go creates the lib.go file by detecting the gurobi and lp_solve versions and then properly writing the cgo directives in lib.go.

The installation of goop failed for me because the code has hardcoded a version of Gurobi into it; make_lib.go solves this problem by looking into the Mac's file system to determine the version of Gurobi installed and then incorporates that into lib.go.

[mojinfu]

hi kwesiRutledge , I am glad that this project is still progressing.

I am also looking for how gurobi works under golang ,
But this project is too old and supports too few gurobi functions. Do you have any other solutions?

[kwesiRutledge]

Thank you for the message, @mojinfu !

This pull request has not gotten a response in ~10 days, so this project might not be active anymore. :/

The only other gurobi package for Go that I know of is gurobi.go. But this package seems to be even older than goop and is also inactive. So, I do not have any other solutions, but if you want to start a new project (maybe a goop2?) then we can collaborate on making one; I'd be willing to make some of the basic features with you as I learn cgo!

[kwesiRutledge]

One follow-up on this, @mojinfu ; I started a new branch of gurobi.go that I think I'll update regularly. If you're still interested in using Gurobi, then feel free to track that as well.

[mojinfu]

hi kwesiRutledge , i did it.
in last two week , i finish my repo gurobi golang sdk. (the idea and part code is from ubnt-intrepid's repo)
and it is based on gurobi 8.1.1 C SDK. CGO used. not very difficult。

The most difficult thing to implement is to implement the callback function in gurobi optimize function, which is input as a parameter.

but sorry ,i'm working for Tsla company , so i can not share my repo or any code .

if you have any question , you can ask me, and i will very happy to answer.
and you can contract with me by email : mynameless@foxmail.com

[mojinfu]

@kwesiRutledge

[kwesiRutledge]

Thanks for the update, @mojinfu !

If I have any questions, then I will be sure to ask you about it through email!