php53: fix bin-names

Add suffix to all files in bin/ (PHP's install skips some even though we
asked it to suffix...).
Use our bin-name for php ('php53') in shell scripts calling it.
php53: move lib/build into lib/php

In Slack 14, the lib/build/ dir has been moved inside of lib/php/, much
cleaner IMO (lib/build/ is way too generically named and anything PHP-lib
should be in lib/php/).  Copied that.
php53: don't use same path for scandir and inidir, causes issues

Using the same dir causes the main php.ini to be loaded twice, resulting at
least in warnings about attempting to load the extension modules twice
(didn't do much further testing as this issue is big enough of itself but
wouldn't be surprised if more issues were caused).

Using /etc/php53/php as the scandir for now but I don't like it much, will be
looking for a better solution later on.
php53: add global Apache configuration file for php53

Contains the generic stuff to make the handler available, user needs to
explicitly enable it for files or directories where they want to use this
version of PHP (default is to still use Slackware's mod_php, php53 is just
an additional option for some specific situations).
php53: adjust slack-desc to php53

Some basic info on the pkg, just a start.