Use a plovr.jar that we build ourselves on the nick-plovr-test branch

Hello dan, 

Please review the following commits I made in branch 'nick-own-plovr'.

a3d5fa44bcb9287af1d3ed2bb792e716f876808a (2013-03-27 11:59:01 -0400)
Use a plovr.jar that we build ourselves on the nick-plovr-test branch

R=dan