Autogen without autogoo

This includes #191 and #192, because otherwise there would be merge conflicts if someone tried to merge them all.

This removes autogenerated files, without the dependence on `autoreconf`.  The main visible difference (mentioned in `INSTALL.txt` is that users now must run `./autogen.sh` before `./configure`.  Additionally, the `.zip` file on github will require `autoreconf` to work correctly.  (If you really want, I can write an alternative that attempts to use `git`, `curl`, and `wget` to get the required files, and only fails if none of these exist.  But I think we want to push people to make use of `git`.  Alternatively, I can make a better `.zip` file which does not depend on `autoreconf`, but which requires hosting somewhere other than github.)

The way it does this is by having travis keep an extra branch up to date with the results of running `./autogen.sh` on a machine with `autoreconf`, and, assuming that `./.git` exists and is a directory, `./autogen.sh` will simply acquire the necessary files from the other branch, if `autoreconf` does not exist.

One of the main benefits of all this is that when we are reviewing pull requests which touch `configure.ac` or `Makefile.am`, we don't have to slog through the changes to all the autogenerated files.

Additionally, this will pave the way to having `./autogen.sh` manage a bundled coq git submodule, if only I can figure out how to fix the problem I'm having trouble with (see https://github.com/HoTT/HoTT/issues/194#issuecomment-23235547).  Perhaps, if this merges, I will already be able to simplify the install procedure slightly by bundling coq, so that users only have to run `git clone` once, and then can `cd` to the subdirectory to install Coq.