Fixup readme

Did a bunch of things with the README:
 * moved version history into its own file
 * moved old release notes into new version history file
 * linked the README to the new file
 * moved issue/apology to dedicated issue: https://github.com/rvirding/lfe/issues/56
 * provided links to docs in source code
 * provided link to new user guide
 * added some basic quick-start instructions