Ignore files generated by Leiningen when working with Clojure.
Make CMake syntax restart from the start.

Otherwise, it gets very confused and stops highlighting a number of
elements correctly.
Activate restoration of 'iskeyword' that was left commented out.

Thanks to John Szakmeister for noticing the mistake in the original
commit (f8c98142).
Merge branch 'small-fixes' of https://github.com/jszakmeister/vimfiles