Remove elisp byte code from repository, since it is non-portable
Mark autoloaded code so that lfe-start is unnecessary

- Magic "autoload cookies" have been added to mark code which should be
  autoloaded.

- When installed via package.el or el-get, autoloads will be generated
  automatically from those marked snippets, resulting in an autoloads
  file which is equivalent to the lfe-start.el file

- The code for file associations etc. and ignored completion extensions
  has been updated to more idiomatic but equivalent snippets

- lfe-start.el could be generated, if desired, from the other code using
  "M-x update-directory-autoloads". I have refrained from doing this.