Last commit breaks format-spec

[DamienCassou]

This should be t

(string= (format-spec "%s" '((?s . "foo"))) "foo")

but triggers an error with latest beacon commit.

[DamienCassou]

The error is:

Args out of range: #<killed buffer>, 3, 10

[dakra]

Took me a bit to find what broke my Emacs yesterday as well. see #57

[Malabarba]

I see what I did wrong, but it's a little odd that this problem never showed up before (the string-match was there already, I just changed the regex).

Anyway, should be fixed on the next build.