56668: Merged V4.1-BUG-FIX (4.1.7) to V4.2-BUG-FIX (4.2.1)
56667: MNT-9774: Merged V4.1.5 (4.1.5.7) to V4.1-BUG-FIX (4.1.7)
56160: MNT-9663: Missing preview for large video files when Alfresco uses AWS S3 storage
Make cache writer aware of backing store writer so that it could return actual size and contentData when cache file is deleted after content was put to backing store.
56186: MNT-9663: Missing preview for large video files when Alfresco uses AWS S3 storage
Add copyright message and class description to BackingStoreAwareCacheWriter
git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@56682 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261