Feature/modulize

CC: @kazeburo

I want gearman-starter.pl to release to CPAN.

So, I adjusted Module formant, added test and wrote documents.

Can you merge and release it or (if you feel bothered with releasing)
let me release it without merge this p-r?

And I warry for licensing. 

I know Gearman itself is applied BSD license and original Makefile.PL of gearman-starter.pl
is too. but I don't know it should be applied BSD license or not.

If no problem, I want to apply Perl License.