URL rewrite, reworked hooks, core function file rename

- htaccess url rewrite
- more hooks in sys-load.php
- renamed sys-pre-init.php to sys-core.php
- new get_url() fetches url as object
- is_https()
- hooks now stored in an object (much cleaner for multidimensions -
line 71)
- no need for $hooks definition before adding/doing hooks
- add_hook arguments can now be single string and converted to array
with is_array() test (line 70)