Adding vista-foia metapackage.

Introduced vista-foia meta-package that depends on the specific package
vista-foia-0.20130405, which in turns contains the M/MUMPS routines for
the FOIA release included in this package. In this way, it is possible
to install multiple versions of vista-foia, and have the vista-foia
package pointing to the most recent one.
Merge branch 'master' of git+ssh://git.debian.org/git/debian-med/vista

Conflicts:
	debian/rules
Better naming for vista-foia version directory.