[WIP] Multi module build

[koppor]

This is a huge step towards #110 and prepares #3421 somehow.

This enables gradle multi module build.

The dependencies of "logic" were not as clean as I thought. I removed dependencies to GUI or moved packages back to gui (shared, remote).

We should get this in ASAP.

Open issues:

• src/main/gen should be removed from version control - generated code like jabref.gui/src/main/gen/org/jabref/logic/importer/fileformat/mods/RoleTermDefinition.java is put under version control; is this desired?
• inherit more from root project avoid duplication of plugins dependencies and tasks (https://docs.gradle.org/current/userguide/multi_project_builds.html)
• GUI does not start: Cannot load file GroupTree.fxml
• Install4J does not find the generated JARs.
• The OO preferences should be fixed (reading/writing not fully supported yet). All other features should work. - done in Prepare multi module build #3913
• jar are not uploaded to CircleCI - are they stored somewhere else? http://builds.jabref.org/multi-module-build/
• Tests not executed on travis. :org.jabref.gui:junitPlatformTest - this works locally though.
• Tests fail on travis. E.g., [main] ERROR org.jabref.logic.l10n.Localization - Messages are not initialized before accessing All entries

[tobiasdiez]

The fxml and css files should lie in the same folder as the view GroupTreeView

[tobiasdiez]

You can just move these methods to JabRefPreferences.

[koppor]

Solved via 9bfea57

Current state: Compiles fine on Windows, but on Linux:

FAILURE: Build failed with an exception.

* Where:
Build file '/home/ubuntu/jabref/org.jabref.logic/build.gradle' line: 73

* What went wrong:
Execution failed for task ':org.jabref.logic:processResources'.
> No signature of method: static org.gradle.api.Project.getRootProject() is applicable for argument types: () values: []

Reproducible via

docker run -it --rm --name my-maven-project -v "d:/git-repositories/jabref/jabref:/usr/src/mymaven" -w /usr/src/mymaven jabref/javafx ./gradlew release

[tobiasdiez]

generated code like jabref.gui/src/main/gen/org/jabref/logic/importer/fileformat/mods/RoleTermDefinition.java is put under version control; is this desired?

[koppor]

That should not happen. We have to remove that code.

I will double check.

[koppor]

This will be frozen until #3733 is merged. Reason: That PR also does huge refactorings.

[koppor]

I close this PR as this is unfinished.

I created #3913 as follow up. The small changes are filed as PRs #3907, #3908, #3909, #3910, #3911, #3912

The only thing not followed-up is the gradle multi-module-build (Co-Authored-By @stefan-kolb). I propose to leave it to @florian-beetz to investigate the gradle scripts and see whether they help him to get JabRef ready for Java9.