Add a top level Makefile

* slime.el: Bump version to 2.0.1

* slime-tests.el (slime-test-ert-for): Use `eval-and-compile' (fixes
  byte-compilation issue).

* Makefile: New file: top level makefile, replaces mkdir.sh and
test.sh. Some elpa targets available, still incomplete.

* .travis.yml (script): Use "make check".

* mkdir.sh: Removed file.

* test.sh: Removed file.