Fixes issue #2482 and adds note in matplotlibrc.template

Three changes:

1. Changed 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.

2. Fixed 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`.

3. Added a note in the `INSTALL` document about the incompatibility of the tight setting for bbox with generating movies using pipe writers, like `ffmpeg`.