buffered input

[so]

> Does shiftFront literally move element n to index 0 and so on? It seems  
> to me that if you do, its going to have horrid performance, and if you  
> don't, then you will eventually run into situations where appendToFront  
> will require a wrap around, which loses you your contiguity, or a  
> reallocation of the buffer.

I think it is basically popFrontN(), and appendToFront() a just append.