validate fromArray in config class to ignore empty tags. If for some strange reason the frontend code drops empty tags, we need to ignore them.

Related to https://github.com/opnsense/core/issues/116

fix for https://github.com/opnsense/core/issues/115 , the process flow remains messy, but shouldn't flush the config data anymore

Even though the webgui is restarted selectively, the other function
runs the complete captiveportal reconfigure and restarts all webguis
again.  I am suspecting this prevents the reload from working properly.

Small whitespace cleanups and style on top.

Submitted by: Ad

Either the RAM requirements have increased, or hardware has
increased.  Simply stating the arbitrary and obvious while
doing things of little value to `fix' the situation it is
probably better to just force an old-fashioned out of memory,
which is mostly the point where the user realises that it is
not going to work anyway.

  `If a globalized variable is unset() inside of a function,
   only the local variable is destroyed. The variable in the
   calling environment will retain the same value as before
   unset() was called.'

via http://php.net/manual/en/function.unset.php