Version sharing (#465) + optional inclusion of subprojects in the roadmap view (#2666).

Each version of a project can be shared with:
* subprojects
* projects in the project hierarchy: ancestors + descendants (needs versions management permission on the root project)
* projects in the project tree: root project + all its descendants (same as above)
* all projects (can be set by admin users only)

Notes:
* when sharing a version of a private project with others projects, its name will be visible within the other projects
* a project with versions used by non descendant projects can not be archived

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@3123 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/fixtures/attachments.yml

@@ -133,4 +133,15 @@ attachments_011:
   filename: picture.jpg
   author_id: 2
   content_type: image/jpeg
-  
+attachments_012:
+  created_on: 2006-07-19 21:07:27 +02:00
+  container_type: Version
+  container_id: 1
+  downloads: 0
+  disk_filename: 060719210727_version_file.zip
+  digest: b91e08d0cf966d5c6ff411bd8c4cc3a2
+  id: 12
+  filesize: 452
+  filename: version_file.zip
+  author_id: 2
+  content_type: application/octet-stream