Fix RSS feed parsing due to changes in go-pkg-xmlx.

Due to the PR jteeuwen/go-pkg-xmlx#16, when using SelectNodes there is no
longer any hidden recursion.  Due to RSS's structure, there is a root document
node.  These two pieces break the RSS parsing.  Fix by first selecting the
root document node, and then selecting the channels for parsing.
Add travis configuration file.

Add travis configuration information, to automatically test my version.