README: Update requirements
README: Update requirements

- Separate requirements section into requirements for running, for building,
and for building from Git.  Add Autotools, pkg-config, and development
headers to the to-build lists.

- Add kernel devel headers to the to-run requirements (for openisr-config)

- Remove SQLite from the requirements list, since we ship it ourselves

- Add ./autogen.sh to the installation summary when building from Git

- Fix version number in the first paragraph

cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr