Fix make uninstall

[ntadej]

The double quotes in make uninstall prevented rm from working properly at least on OS X

[benjamin-weiss]

Why do you want to uninstall it? Metropolis is awesome. 😄

[matze]

Besides the reason given by @benjamin-weiss, we should look for another solution because of more severe implications: The quotes were introduced because passing directory name with spaces in them might delete unrelated directories.

[ntadej]

@benjamin-weiss I made a personal fork with some changed colors and defaults, so I renamed it and wanted to test if makefile still works 😊

@matze The current uninstall does not work. I can try iterating over the files and appending path to each one, but I'm not very fluent in make.

[rchurchley]

What if we just add quotes to the problematic directory strings? That is, instead of adding quotes to each command in make uninstall, we define

DESTDIR ?= "$(shell kpsewhich -var-value=TEXMFHOME)"

instead of

DESTDIR ?= $(shell kpsewhich -var-value=TEXMFHOME)

I think this should properly escape the things that need to be escaped without breaking the uninstall script.