add META repository information for metacpan

This relies on a feature in ExtUtils::MakeMaker 6.46 and above, but does
not appear to be fatal on an earlier version I tested. I believe this
means that 6.46 or above needs to be used when building the Makefile
used for 'make dist', if that's your build chain.
ignore vim swp files
Merge pull request #4 from preaction/add-meta

Add meta repository information for metacpan