hardlink: Add formula for 0.2.0 & 0.3.0_rc1

Add formula for the hardlink project from
http://jak-linux.org/projects/hardlink/.

Hardlink replaces multiple copies of a file with
hardlinks. This formula includes both the stable
and experimental versions.

A previous pull request was opened for the Python
version but was closed in favor of a formula
for the C version. 

https://github.com/mxcl/homebrew/pull/12068