Media and Wikipedia

Myriad of small changes, plus three new functions that could be useful:
brain2.loading() prints a generic loading message;
brain2.group_together(sentence) trys to lump keywords together so they
can be searched for easier; brain2.forward(sentence, keyword) is used
if you get something you know is not yours, so you send it back with a
keyword that should find the right module. Two new modules are media.py
for basic play/pause stuff, which will hopefully get deeper soon; and
wikipedia.py, which can do basic research for you. finder.py got a
quick tweak so it can open URLs as well.