adding some static files back

for debugging, it's better to use copies on the server than the hotlinked files.
correct paths to image files for datatables headers
conditionally load static files or hotlink
change active cell class to "selected"

"active" means a bunch of fuelux styles get applied and mess things up
add TEST_CORPUS_PATH settings variable

at least for testing purposes, we're just going to assume the server has one folder of music files for importing. This mechanism will later be replaced by taking files right from the "elvis-site" project.
remove absolute import

it was causing some weird errors to import stuff from the containing directory? Python magic I guess.
add project settings to template context

to tell whether we're debugging or not!
importer pane works

now, that's a lot of javascript!
remove unused code

because we can always get it back with the magic of version control.
Merge remote-tracking branch 'origin/visX-devel' into visX-devel