Version string now dynamically generated

This was motivated by Git itself, which uses `git describe` output to
generate the version number relative to the last tag. The format of it fits
fairly cleanly into the existing ease.js versioning scheme, but the m4
macro had to modified slightly to handle additional dashes.
Makefile will now write version file on dist
Closure compiler --language_in=ECMASCRIPT5_STRICT

This not only resolves the error triggered by the use of `super`, but also
is more proper, since that is what ease.js is being developed for; I handle
all ES3 fallback considerations myself.

Note that the build will now produce warnings, but the lines producing them
will be removed shortly in favor of a new API.
AC_INIT e-mail changed to bug-easejs@gnu.org
Forcing version regen on combine if in git repo

This will re-run `autoconf` if it is detected that the user is within the
git repository, which will force `configure` to be regenerated; this is
necessary, since `configure.ac` contains the version macros.
Dynamically generating version string