Move spec file to top level.
Adhere to libvmod-example best practice.
Import debian packaging files from vmod-example.
Update header and require recent autoconf.
Add /usr/sbin to path when looking for varnishd.
Pass VMOD_DIR to make distcheck

The VMOD_DIR returned from pkg-config does not take prefix and similar
variables into account. Make sure to pass an explicit VMOD_DIR that
the build process has write access to.

Fixes #8

Conflicts:
	Makefile.am
Work against a working distcheck.