Add build.xml v1.5.4 to Media Viewers project, refactor project.xml to override the new sub-tasks

git-svn-id: https://share-extras.googlecode.com/svn/trunk/Media Preview@1458 a3f5c567-fd0f-3a89-9b71-a290c5a5f590
Prevent document config items being saved to local storage if values are null

git-svn-id: https://share-extras.googlecode.com/svn/trunk/Media Preview@1459 a3f5c567-fd0f-3a89-9b71-a290c5a5f590
Increment version

git-svn-id: https://share-extras.googlecode.com/svn/trunk/Media Preview@1460 a3f5c567-fd0f-3a89-9b71-a290c5a5f590