Update setupEmacs() so that it builds a package

[d-torrance]

We now build a tarball and install it using package-install-file. This way, the package files will be byte-compiled and it will appear with the list of other packages that users install from melpa, etc.

[mahrud]

What's the advantage here, and are the tests testing anything?

A big disadvantage seems to be that it doesn't work if the user has a variant of emacs installed or if the path to emacs is not known by M2.

[d-torrance]

Several advantages:

• The .el files are byte-compiled when the package is installed, which will improve performance.
• It integrates the M2 package with the rest of the emacs package ecosystem. For example, it will appear when running package-list-packages.
• Consistency with the Debian/Ubuntu package, which has been installing the Emacs package like this for years.

Good point regarding M2 not knowing how to find emacs. Perhaps we could add setupEmacs(String) that the user could use if just emacs doesn't work?

It would definitely be good to test this with several Emacs variants.

[mahrud]

I don't know what's the idea with the last few commits but I'm highly opposed. M2 documentation doesn't need lisp syntax highlighting ... you can put extra stuff on the wiki if absolutely necessary, but even then I think it's unnecessary.

[d-torrance]

Fair enough -- I guess I did go a bit overboard! I'll remove them.

[d-torrance]

I think this is ready now. Now, the code in .emacs-Macaulay2 first checks to see if the M2 function is defined (which it should be if package installation was successful). But if not, it falls back to the old behavior of adding the Emacs directory to load-path and loading M2-init.el.