Move away from Autotools

[pniedzielski]

Cask is a modern dependency manager and build too for elisp packages. It supports declaring and installing dependencies (like Gemfiles for Ruby), building the software, running automated ERT tests, and creating an ELPA package. Many elisp packages have been moving to Cask recently, and it's easier to maintain than Autotools.

For an example Cask file, see Flycheck's.

We have the additional caveat that we have a C code component as well. We will need to look at whether Cask can handle this, or what we can do about this.

[pniedzielski]

Rather than using Cask, we can remove all use of autotools for at least the elisp code. For the C code, Cask doesn't seem like a good match anyway.

See #7.