Solve issue #2482

First commit changes the order of arguments in the call to `ffmpeg`. Now output options go with the output file instead of the input file. This avoids an issue with `ffmpeg 2.x` rejecting the call.

Second commit fixes a bug where `xrange()` was assumed (incorrectly) to be a generator. It is in fact some sort of lazy list, so it does not have the `__next__()` method generators have.The bug manifested itself when calling `FuncAnimate()` with a constant number of frames, like in `examples/animation/basic_example.py`.

Third commit adds a note in the `INSTALL` document about the incompatibility of the `tight` setting for `bbox` with generating movies using pipe writers, like `ffmpeg`.