Travis-CI needs update for JDK 6?

[SethTisue]

at #179 , it looks like whatever we're doing to get JDK 6 on Travis-CI isn't working anymore

someone might like to take a look at what https://github.com/scala/scala-xml/blob/master/.travis.yml is doing and see if it needs to be applied here, or what

[SethTisue]

if scala/scala-xml#271 is successful maybe we can just copy it /cc @ashawley

[SethTisue]

fixed by @sudohalt in #184. and thanks @ashawley for figuring this out