We're not using AC_FUNC_MALLOC correctly; remove it.

When AC_FUNC_MALLOC is used, Autoconf requires that the program provides
a replacement for malloc(), but we don't.
http://lists.gnu.org/archive/html/autoconf/2005-02/msg00142.html

AC_FUNC_MALLOC is only useful if the program calls malloc(0). AFAIK, swfmill
doesn't do this. http://lists.gnu.org/archive/html/autoconf/2003-02/msg00018.html

I'm not sure if this ever works for C++ programs...
Add scripts to cross-compile for Windows on the Vagrant VM.

Messy for now, but it works.
Add script to create distributables.

Messy for now, but it does the trick.
Ignore version-numbered .vagrant files created by newer versions of Vagrant.
Don't fail if directory already exists.
Add Mitch Walker to AUTHORS (belatedly).
Merge branch 'master' into auto-ptr