Make stable .deb packages versioned [#73]

By adding a version number to debian package, it is possible
to easily rebuild packages of the same binary version;
e.g. HHVM 3.3.0 could be built as 3.3.0-1 and, if needed
(like because of bumped dependencies, also as 3.3.0-2 and so on.
Merge pull request #76 from Majkl578/deb-package-versioned

Make .deb packages versioned