Upgrade VariantSync to newest Eclipse and FeatureIDE version

[pmbittner]

Currently, VariantSync only runs with very old versions of Eclipse and FeatureIDE due to numerous changes in the FeatureIDE library.
VariantSync should be upgraded to run with the newest Version v3.7.0 (https://featureide.github.io/) of FeatureIDE.

[wurstbroteater]

Problem occurrence & description

1. de.tubs.variatnsync.core :

   • Several methods of ComposerExtensionClass have changed.

2. de.tubs.variantsync.core.managers :

   • Type Mismatch - expected IFile but got Path.

3. de.tubs.variantsync.core.managers.data

   • Type Mismatch - expected IFile but got Path.

4. de.tubs.variantsync.core.managers.persistence

   • Method headers of overloaded methods have changed.

5. de.tubs.variantsync.core.patch

   • CoreExtensionLoader has been removed.

6. de.tubs.variantsync.core.patch.base

   • Methods of IDeltaFactory<Chunk> have changed.

7. Context.setPossibeWords(?????))

Summary

• Most of these problems occur because the usage of the IFile interface is deprecated and should be replaced with Path.

(* Differences between IPersistentFormat and APersistentFormat, CoreExtensionLoader, IExtensionLoader and EclipseExtensionLoader ?)

Solutions & Decisions

• Addressing 1-3 :
  (- ComposerExtensionCLass ua forPreprocessor Integration)

  • Change IFile to Path (@tcerny)

• Compare : 4-6 setExtensionLoader and setExtensionLoaderInternal. What does CoreExtensionLoader (DefaultDeltaFactory.java) and refactoring old methods. (@jeremiaheinle)

• Addressing 7:

  • The method has been deleted in FeatureIDE since this commit
    FeatureIDE/FeatureIDE@b679c39#diff-02b7a28d524fe3c717b03a9621030e760993f27c394403d3d837e36e4c4489fa
    Since there is no provision of a new method, it can be deleted. (@wurstbroteater)