Update org.xhtmlrenderer dependency to flying-saucer-pdf

[timbonicus]

The rendering plugin is using org.xhtmlrenderer:core-renderer:R8, which is rather outdated. I was looking for support of the HTML TITLE tag to set the PDF title, which was added 5 years ago.

It appears the updated dependency is org.xhtmlrenderer:flying-saucer-pdf. Is it possible to get an update to this newer dependency?

[graemerocher]

If I recall I believe the issue is related to licensing and itext changing from GPL to AGPL

[mctolentino]

Looks like it's safe to update to a newer dependency since flying-saucer-pdf is now using itext 2.1.7 as a dependency:
https://github.com/flyingsaucerproject/flyingsaucer/blob/master/flying-saucer-pdf/pom.xml

They've separated the itext5.5 dependent sources:
https://github.com/flyingsaucerproject/flyingsaucer/tree/master/flying-saucer-pdf-itext5

[mctolentino]

I've created a pull request with the updated dependencies. I've encountered some issues with Travis, so I also updated some of the build configurations. Can anyone take a look at it? Thanks!

Pull Request: #38