configure.ac: check for <rdma/fabric.h>
configure: modernize for recent versions of the GNU Autotools

- Use autoreconf in autogen.sh instead of listing individual steps
- Put bozo directory check in autogen.sh
- Update AC_INIT and AM_INIT_AUTOMAKE to use modern forms
- Add the use of AM_PROG_AR, if it exists (it is required in recent
  versions of Automake)
- Use AM_PROG_CC_C_O to build programs outside their source directories
Add initial .gitignore file