Extract the name check to a separate subroutine

It's easier to reuse in aliases and also easier to adjust if someone wants to
subclass this to make their own exceptions or allow single char words or
something.
Eliminate an annoying uninit warning when listing aliases
Make the karma alias feature a bit more robust

* No longer allows self-referential aliases.
* Prevents aliases to words that won't get scored.
* Sets the score to 0 for aliased things to allow the JOIN to count the score
  correctly for things that haven't yet been scored.