Initial commit (with new comments and new remove method)
Comments (mostly just changing the length of lines)
Comments, and removal.
Removal and added comments in AbstractLayer about the interposition of add and remove
Initial commit of Viewport
Added Iterability
Abstracted to Viewport interface
Javadoc description and reordering
Removed getZoomFactor (which should have been protected, not public)
Javadoc description and error checking in constructor
Initial commit and comments.