Changed builtins to use new command style.

As a piecemeal change to make plugins use new command style started with builtins. Now commands are saved in the event object by the plugin. When a command is received, the string following the ! is checked for existance in each plugin, then all of the rest is split on the space and passed to the command as an array of arguments.
Swapped builtin check to standard check function.

Also created an array that prevents plugins from being loaded until manually added. This allows us to get it all working one piece at a time.
Fixed builtin_found function return.
Added alarm plugin to new command functionality.
Revamped alias.js to new command structure.
Made 'to' optional in alias command.