[PDE-Build] Copy Eclipse-BundleShape and other headers in wrapped states

For wrapped OSGi States obtained from pde.core/ui the Manifest
'Eclipse-BundleShape' entries, besides others, were not copied into the
bundle's user-object Properties. This had the consequence that in
ShapeAdvisor.getUnpackClause() the value of that entry could never be
considered.
The method only used to return the expected boolean value because of
corresponding unpack-attributes in 'plugin' entries of feature.xml
files. But since the removal of that otherwise unused attribute in [1]
this makeshift was gone and ShapeAdvisor.getUnpackClause() always return
false leading to all bundles in an exported product being in jar-shape,
even if the 'Eclipse-BundleShape' entry in the MANIFEST.MF told
something different.

Fixes #995

[1] - #770

build/org.eclipse.pde.build/src/org/eclipse/pde/internal/build/site/PDEState.java

@@ -104,6 +104,10 @@ public PDEState(PDEUIStateWrapper initialState) {
 		addedBundle = new ArrayList<>();
 		unqualifiedBundles = new ArrayList<>();
 		//forceQualifiers();
+		for (BundleDescription bundle : state.getBundles()) {
+			Dictionary<String, String> manifest = loadManifest(new File(bundle.getLocation()));
+			rememberManifestEntries(bundle, manifest, MANIFEST_ENTRIES);
+		}
 	}
 
 	public PDEState() {