Created the class for cleaning unused site images from the liferay-docs
repository.
Wrote CleanImagesStieMain.Java
Class is fully functional, deleting unused images as expected. Still
needs to be cleaned up and spit the proper messages in the console.
Edited CleanImagesSiteMain.Java and added new "clean-images" task to
build-site-common.xml
Removed comments from class, formatted.
Ran ant deploy to put new class in liferay-doc-utils.jar
Move deprecation policy documentation into Reference web content backup file.
Remove unneeded liferay releases tutorial as the material is covered in Discover > Portal and the deprecation material is in the web content on the Develop > Reference page.
LRDOCS-1392 Build .METADATA file for the ZIPs
Merge branch 'master' into build-metadata-file
LRDOCS-1392 Remove the "prepare" dependency from target create-metadata-file. No need to create/copy files to a build directory.
Merge branch 'clean-images-site-main' of https://github.com/rbohl/liferay-docs into clean-site-images
Minor cleanup to CleanImagesSiteMain
Refresh liferay-doc-utils.jar
Merge branch 'build-metadata-file' into clean-site-images

Conflicts:
	build-site-common.xml
Merge pull request #1025 from jhinkey/deprecation-policy

Deprecation policy
Merge pull request #1026 from jhinkey/build-metadata-file

LRDOCS-1392 Build .METADATA file for the ZIPs
Merge pull request #1027 from jhinkey/clean-site-images

Clean site images