Also, pass list of files to be byte-compiled as a lisp form on the
command line instead of stdin, and use a more future-proof method of
determining which elisp files the child process needs to load.
Same reason as in 11ef806a. The result of this function is passed to
`el-get-start-process-list` with a `:shell t` option, which results in
shell-quoting. So doing it here is redundant and potentially harmful.
This includes teaching methods that they now work with a symbolp PACKAGE,
some more cleaning up, and some load-path adjustments now that a part of the
code is in a subdirectory (methods).
Also include some of the tests used to convince oneself that the refactoring
didn't break any and all use cases for el-get, with some rough documentation
about how to use them.
