Test resource directories overlaps between plugins and jib-core

[TadCordle]

In jib-core, we have a resources/application directory. In the plugins, we also have a resources/application directory. Travis doesn't seem to like this; I ran into an issue with #1347 where jib-core tests pass by themselves, but fail when they're re-run after building the plugins/plugins-common, because it seems to use the plugins' resources/application directory instead of jib-core's.

Example:

• jib-core passes
• but plugins-common fails due to additional files being added

I avoided this issue in #1347 because of unrelated code changes, but it might make sense to fix this.