base: new filter: tokens.

Maps directly onto `string:tokens/2` from stdlib.
doc: bump copyright year to 2013.
core: Change hostalias value to list.

Site config could have multiple hostalias keys. This could be an issue
when using files in config.d, because the settings are merged with
`lists:ukeymerge` which does not support duplicate keys.

This is solved by changing hostalias syntax to the following format:
```
{hostalias, ["a.example.com", "b.example.com", "c.example.com"]}
```
doc: Remove repeated keys from docs.

The repeated configuration keys are no longer possible.
doc: touch up the docs for multiple site config files.

Fixes #651.
mod_admin: template updates and cleanup.

Geomap location is now included if the address part is included.
Connection items are now more standard list items, can also be used in main column (for mod_admin_frontend).
Small language corrections.
i18n widget can now have a top language-neutral part.
i18n widget can now optionally have a title and minifier.
edit_date.tpl now uses a timepicker (Fixes #621)
Refactored cropcenter code, to work better in mod_admin_frontend.
mod_admin_frontend: make language, access control, and publication period accessible.
mod_menu: added 'copy' option to menu list. Cleanup of some templates.
mod_base: added timepicker js, and shorten.js.
mod_base: lager warning if a sort couldn't be delegated.
core: also copy files if copying a media item. Fixes #647
mod_artwork: added font-based icons from http://fortawesome.github.io/Font-Awesome/
core: fix syntax error in erlang config file.
mod_admin_frontend: normalize name of css file to name of module.
core: fix for name of zotonic emqtt auth module.