Window menu: Make Screencast (should be Save?, to match screenshot?) option. 

Thought of setting the operator context before so it wouldnt invoke the confirmation dialog, but better leave it by default to confirm since it might be clicked by mistake and start dumping video/image-sequence and can get annoying.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54167 954f8c5b-7b00-dc11-b283-0030488c597c