Add basic Installing to README

[jxu]

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As far as I can tell installing is done the standard way with make and sudo make install. Installing instructions in the README would be appreciated.

[dmsc]

Hi!

Yes, you can make a PR with the update at the end of the README. I don´t usually "install" programs myself, I comply copy/link them to ~/bin/ (or ~/.local/bin).

Have Fun!