Run providers in separate classpath

[quidryan]

Ideally we'd want the providers to download their dependencies to a configuration, then use that configuration. This would let us not have dependencies on every provider client jar (e.g. p4java, jgit). The alternative is to make the dependencies optional, but then the user would have to know beforehand which jar to pull in ahead of time, which defeats the convenience of this plugin.

[elygre]

I have encountered a problem when using asciidoctor-pdf along with the nebula-info plugin, where jruby related code ends up throwing an exception. The problem is a classpath conflict between com.jcraft:jclib:1.0.7 (introduced by nebula-info) and jruby (which requires, and includes, jclib-1.1.2).

Could this problem be related to what you describe in this issue?

(see https://github.com/elygre/asciidoctor-pdf-final-class and http://discuss.asciidoctor.org/Using-asciidoctorj-pdf-from-gradle-tp2731p2986.html for more information on the conflict)