Squashed commit of the following:

commit 15f71cdf4e559ec5e8fc366df0bd799b309444a2
Author: affinehat <krs@umd.edu>
Date:   Mon Jun 16 14:41:50 2014 -0400

    Fix another typo

commit 6ad95a0a0c16b9ee90ceaf5166195e8c2b1e5dce
Author: affinehat <krs@umd.edu>
Date:   Mon Jun 16 14:40:03 2014 -0400

    Fix typo

commit 3af5f77a763e4fd1bf48e187a226ea6d91b80bff
Author: affinehat <krs@umd.edu>
Date:   Mon Jun 16 14:38:50 2014 -0400

    Fix bug: clicks triggering on node drag

    Click events are now suppressed when nodes are dragged

commit 43817291abee8c7a9a7194900faf25f0bb40f68e
Author: affinehat <krs@umd.edu>
Date:   Mon Jun 16 12:04:18 2014 -0400

    Fixed logic; topologies are now linked to child nodes

commit 0d7050b5b5f8b57f993aedba4fa7e9fab6e45b05
Author: affinehat <krs@umd.edu>
Date:   Mon Jun 16 11:42:29 2014 -0400

    Add support for hidden links + fix link display bug

    Fixed bug where links do not show when not declared as alias on both
    end nodes

commit 8dc935b556191389f853af74708b08bbec2510ac
Author: affinehat <krs@umd.edu>
Date:   Mon Jun 16 11:09:38 2014 -0400

    Add missing hypervisor service type + icon

commit 88891ff9305994209e6be0ccca6ebf4599346caf
Author: affinehat <krs@umd.edu>
Date:   Mon Jun 16 11:06:41 2014 -0400

    Add feature to toggle visibility of topology nodes

    Clicking a topology node toggles visibility of all child nodes

    Fixed bug preventing nodes with no top level NML or MRS elements from
    being displayed