Adding PkgVersion and PodWeaver dzil plugin

With this addition the package version gets written into the .pm file, which is relevant for version checks on requirements. PodWeaver guarantees that the documentation of the generated .pm file is proper. Please release a version with this fi ASAP :) Thanks in advance.
Merge pull request #1 from Getty/patch-1

Adding PkgVersion and PodWeaver dzil plugin